@article{RectorIntziegianniMuelleretal.2017,
  author    = {Rector, Michael V. and Intziegianni, Konstantina and M{\"u}ller, Steffen and Mayer, Frank and Cassel, Michael},
  title     = {Reproducibility of an ankle joint rotation correction method for assessment of Achilles tendon elongation},
  series = {Isokinetics and exercise science : official journal of the European Isokinetic Society},
  volume    = {25},
  journal   = {Isokinetics and exercise science : official journal of the European Isokinetic Society},
  number    = {1},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {0959-3020},
  doi       = {10.3233/IES-160644},
  pages     = {47 -- 52},
  year      = {2017},
  abstract  = {BACKGROUND: The Achilles tendon (AT) requires optimal material and mechanical properties to function properly. Calculation of these properties depends on accurate measurement of input parameters (i.e. tendon elongation). However, the measurement of AT elongation with ultrasound during maximum voluntary isometric contraction (MVIC) is overestimated by ankle joint rotation (AJR). Methods to correct the influence of this rotation on AT elongation exist, yet their reproducibility in clinical settings is unknown. OBJECTIVE: To evaluate the test-retest reproducibility of AT elongation during MVIC after AJR correction. METHODS: Ten participants attended test and retest measurements where they performed plantar-flexion MVIC on a dynamometer. Simultaneously, ultrasound recorded AT elongation as the displacement of the medial gastrocnemius-myotendinous junction, while an electrogoniometer measured AJR. The ankle was then passively rotated to the AJR achieved during MVIC and AT elongation again determined. Elongation was corrected by subtracting this passive AT elongation from the total AT elongation during MVIC. Reproducibility was evaluated using ICC (2.1), test-retest variability (TRV, \%), Bland-Altman analyses (Bias +/- LoA [1.96*SD]) and standard error of the measurement (SEM). RESULTS: Corrected AT elongation reproducibility exhibited an ICC = 0.79, SEM = 0.2 cm and TRV = 20 +/- 19\%. Bias +/- LoA were determined to be 0.0 +/- 0.8 cm. CONCLUSIONS: Using this ultrasound and electrogoniometer-based method, corrected AT elongation can be assessed reproducibly.},
  language  = {en}
}
@article{IntziegianniCasselRaufetal.2016,
  author    = {Intziegianni, Konstantina and Cassel, Michael and Rauf, S. and White, S. and Rector, Michael V. and Kaplick, Hannes and Wahmkow, Gunnar and Kratzenstein, S. and Mayer, Frank},
  title     = {Influence of Age and Pathology on Achilles Tendon Properties During a Single-leg Jump},
  series = {International journal of sports medicine},
  volume    = {37},
  journal   = {International journal of sports medicine},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/s-0042-108198},
  pages     = {973 -- 978},
  year      = {2016},
  abstract  = {Prevalence of Achilles tendinopathy increases with age leading to a weaker tendon with predisposition to rupture. Conclusive evidence of the influence of age and pathology on Achilles tendon (AT) properties remains limited, as previous studies are based on standardized isometric conditions. The study investigates the influence of age and pathology on AT properties during single-leg vertical jump (SLVJ). 10 children (C), 10 asymptomatic adults (A), and 10 tendinopathic patients (T) were included. AT elongation [mm] from rest to maximal displacement during a SLVJ on a force-plate was sonographically assessed. AT compliance [mm/N]) and strain [\%] was calculated by dividing elongation by peak ground reaction force [N] and length, respectively. One-way ANOVA followed by Bonferroni post-hoc correction (=0.05) were used to compare C with A and A with T. AT elongation (p=0.004), compliance (p=0.001), and strain were found to be statistically significant higher in C (27 +/- 3mm, 0.026 +/- 0.006[mm/N], 13 +/- 2\%) compared to A (21 +/- 4mm, 0.017 +/- 0.005[mm/N], 10 +/- 2\%). No statistically significant differences (p0.05) was found between A and T (25 +/- 5mm, 0.019 +/- 0.004[mm/N], 12 +/- 3\%). During SLVJ, tendon responded differently in regards to age and pathology with children having the most compliant AT. Higher compliance found in healthy tendons might be considered as a protective factor against load-related injuries.},
  language  = {en}
}
@article{RischCasselMayer2017,
  author    = {Risch, Lucie and Cassel, Michael and Mayer, Frank},
  title     = {Acute effect of running exercise on physiological Achilles tendon blood flow},
  series = {Scandinavian journal of medicine \& science in sports},
  volume    = {28},
  journal   = {Scandinavian journal of medicine \& science in sports},
  number    = {1},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0905-7188},
  doi       = {10.1111/sms.12874},
  pages     = {138 -- 143},
  year      = {2017},
  abstract  = {Sonographically detectable intratendinous blood flow (IBF) is found in 50\%-88\% of Achilles tendinopathy patients as well as in up to 35\% of asymptomatic Achilles tendons (AT). Although IBF is frequently associated with tendon pathology, it may also represent a physiological regulation, for example, due to increased blood flow in response to exercise. Therefore, this study aimed to investigate the acute effects of a standardized running exercise protocol on IBF assessed with Doppler ultrasound (DU) Advanced dynamic flow in healthy ATs. 10 recreationally active adults (5 f, 5m; 29 +/- 3years, 1.72 +/- 0.12m, 68 +/- 16kg, physical activity 206 +/- 145minute/wk) with no history of AT pain and inconspicious tendon structure performed 3 treadmill running tasks on separate days (M1-3) with DU examinations directly before and 5, 30, 60, and 120minutes after exercise. At M1, an incremental exercise test was used to determine the individual anaerobic threshold (IAT). At M2 and M3, participants performed 30-minute submaximal constant load tests (CL1/CL2) with an intensity 5\% below IAT. IBF in each tendon was quantified by counting the number of vessels. IBF increased in five ATs from no vessels at baseline to one to four vessels solely detectable 5minutes after CL1 or CL2. One AT had persisting IBF (three vessels) throughout all examinations. Fourteen ATs revealed no IBF at all. Prolonged running led to a physiological, temporary appearance of IBF in 25\% of asymptomatic ATs. To avoid exercise-induced IBF in clinical practice, DU examinations should be performed after 30minutes of rest.},
  language  = {en}
}
@article{QuarmbyZhangGeisleretal.2023,
  author    = {Quarmby, Andrew and Zhang, Martin and Geisler, Moritz and Javorsky, Tomas and Mugele, Hendrik and Cassel, Michael and Lawley, Justin},
  title     = {Risk factors and injury prevention strategies for overuse injuries in adult climbers},
  series = {Frontiers in sports and active living},
  volume    = {5},
  journal   = {Frontiers in sports and active living},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {2624-9367},
  doi       = {10.3389/fspor.2023.1269870},
  pages     = {13},
  year      = {2023},
  abstract  = {Introduction Climbing is an increasingly popular activity and imposes specific physiological demands on the human body, which results in unique injury presentations. Of particular concern are overuse injuries (non-traumatic injuries). These injuries tend to present in the upper body and might be preventable with adequate knowledge of risk factors which could inform about injury prevention strategies. Research in this area has recently emerged but has yet to be synthesized comprehensively. Therefore, the aim of this study was to conduct a systematic review of the potential risk factors and injury prevention strategies for overuse injuries in adult climbers. Methods This systematic review was conducted in accordance with the PRISMA guidelines. Databases were searched systematically, and articles were deemed eligible based upon specific criteria. Research included was original and peer-reviewed, involving climbers, and published in English, German or Czech. Outcomes included overuse injury, and at least one or more variable indicating potential risk factors or injury prevention strategies. The methodological quality of the included studies was assessed with the Downs and Black Quality Index. Data were extracted from included studies and reported descriptively for population, climbing sport type, study design, injury definition and incidence/prevalence, risk factors, and injury prevention strategies. Results Out of 1,183 records, a total of 34 studies were included in the final analysis. Higher climbing intensity, bouldering, reduced grip/finger strength, use of a "crimp" grip, and previous injury were associated with an increased risk of overuse injury. Additionally, a strength training intervention prevented shoulder and elbow injuries. BMI/body weight, warm up/cool downs, stretching, taping and hydration were not associated with risk of overuse injury. The evidence for the risk factors of training volume, age/years of climbing experience, and sex was conflicting. Discussion This review presents several risk factors which appear to increase the risk of overuse injury in climbers. Strength and conditioning, load management, and climbing technique could be targeted in injury prevention programs, to enhance the health and wellbeing of climbing athletes. Further research is required to investigate the conflicting findings reported across included studies, and to investigate the effectiveness of injury prevention programs. Systematic Review Registrationhttps://www.crd.york.ac.uk/, PROSPERO (CRD42023404031).},
  language  = {en}
}
@misc{WojcinskiDupontSchmidtetal.2012,
  author    = {Wojcinski, Sebastian and Dupont, Jennifer and Schmidt, Werner and Cassel, Michael and Hillemanns, Peter},
  title     = {Real-time ultrasound elastography in 180 axillary lymph nodes},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {626},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-43158},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431584},
  pages     = {12},
  year      = {2012},
  abstract  = {Background To determine the general appearance of normal axillary lymph nodes (LNs) in real-time tissue sonoelastography and to explore the method′s potential value in the prediction of LN metastases. Methods Axillary LNs in healthy probands (n=165) and metastatic LNs in breast cancer patients (n=15) were examined with palpation, B-mode ultrasound, Doppler and sonoelastography (assessment of the elasticity of the cortex and the medulla). The elasticity distributions were compared and sensitivity (SE) and specificity (SP) were calculated. In an exploratory analysis, positive and negative predictive values (PPV, NPV) were calculated based upon the estimated prevalence of LN metastases in different risk groups. Results In the elastogram, the LN cortex was significantly harder than the medulla in both healthy (p=0.004) and metastatic LNs (p=0.005). Comparing healthy and metastatic LNs, there was no difference in the elasticity distribution of the medulla (p=0.281), but we found a significantly harder cortex in metastatic LNs (p=0.006). The SE of clinical examination, B-mode ultrasound, Doppler ultrasound and sonoelastography was revealed to be 13.3\%, 40.0\%, 14.3\% and 60.0\%, respectively, and SP was 88.4\%, 96.8\%, 95.6\% and 79.6\%, respectively. The highest SE was achieved by the disjunctive combination of B-mode and elastographic features (cortex >3mm in B-mode or blue cortex in the elastogram, SE=73.3\%). The highest SP was achieved by the conjunctive combination of B-mode ultrasound and elastography (cortex >3mm in B-mode and blue cortex in the elastogram, SP=99.3\%). Conclusions Sonoelastography is a feasible method to visualize the elasticity distribution of LNs. Moreover, sonoelastography is capable of detecting elasticity differences between the cortex and medulla, and between metastatic and healthy LNs. Therefore, sonoelastography yields additional information about axillary LN status and can improve the PPV, although this method is still experimental.},
  language  = {en}
}
@article{RischWochatzMesserschmidtetal.2017,
  author    = {Risch, Lucie and Wochatz, Monique and Messerschmidt, Janin and Engel, Tilman and Mayer, Frank and Cassel, Michael},
  title     = {Reliability of evaluating achilles tendon vascularization assessed with doppler ultrasound advanced dynamic flow},
  series = {Journal of ultrasound in medicine},
  volume    = {37},
  journal   = {Journal of ultrasound in medicine},
  number    = {3},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0278-4297},
  doi       = {10.1002/jum.14414},
  pages     = {737 -- 744},
  year      = {2017},
  abstract  = {The reliability of quantifying intratendinous vascularization by high-sensitivity Doppler ultrasound advanced dynamic flow has not been examined yet. Therefore, this study aimed to investigate the intraobserver and interobserver reliability of evaluating Achilles tendon vascularization by advanced dynamic flow using established scoring systems. Methods-Three investigators evaluated vascularization in 67 recordings in a test-retest design, applying the Ohberg score, a modified Ohberg score, and a counting score. Intraobserver and interobserver agreement for the Ohberg score and modified Ohberg score was analyzed by the Cohen kappa and Fleiss kappa coefficients (absolute), Kendall tau b coefficient, and Kendall coefficient of concordance (W; relative). The reliability of the counting score was analyzed by intraclass correlation coefficients (ICC) 2.1 and 3.1, the standard error of measurement (SEM), and Bland-Altman analysis (bias and limits of agreement [LoA]). Results-Intraobserver and interobserver agreement (absolute/relative) ranged from 0.61 to 0.87/0.87 to 0.95 and 0.11 to 0.66/0.76 to 0.89 for the Ohberg score and from 0.81 to 0.87/0.92 to 0.95 and 0.64 to 0.80/0.88 to 0.93 for the modified Ohberg score, respectively. The counting score revealed an intraobserver ICC of 0.94 to 0.97 (SEM, 1.0-1.5; bias, -1; and LoA, 3-4 vessels). The interobserver ICC for the counting score ranged from 0.91 to 0.98 (SEM, 1.0-1.9; bias, 0; and LoA, 3-5 vessels). Conclusions-The modified Ohberg score and counting score showed excellent reliability and seem convenient for research and clinical practice. The Ohberg score revealed decent intraobserver but unexpected low interobserver reliability and therefore cannot be recommended.},
  language  = {en}
}
@article{MuellerMuellerStolletal.2016,
  author    = {M{\"u}ller, Steffen and M{\"u}ller, Juliane and Stoll, Josefine and Prieske, Olaf and Cassel, Michael and Mayer, Frank},
  title     = {Incidence of back pain in adolescent athletes},
  series = {BMC sports science, medicine \& rehabilitation},
  volume    = {8},
  journal   = {BMC sports science, medicine \& rehabilitation},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {2052-1847},
  doi       = {10.1186/s13102-016-0064-7},
  pages     = {5},
  year      = {2016},
  abstract  = {Background Recently, the incidence rate of back pain (BP) in adolescents has been reported at 21\%. However, the development of BP in adolescent athletes is unclear. Hence, the purpose of this study was to examine the incidence of BP in young elite athletes in relation to gender and type of sport practiced. Methods Subjective BP was assessed in 321 elite adolescent athletes (m/f 57\%/43\%; 13.2 ± 1.4 years; 163.4 ± 11.4 cm; 52.6 ± 12.6 kg; 5.0 ± 2.6 training yrs; 7.6 ± 5.3 training h/week). Initially, all athletes were free of pain. The main outcome criterion was the incidence of back pain [\%] analyzed in terms of pain development from the first measurement day (M1) to the second measurement day (M2) after 2.0 ± 1.0 year. Participants were classified into athletes who developed back pain (BPD) and athletes who did not develop back pain (nBPD). BP (acute or within the last 7 days) was assessed with a 5-step face scale (face 1-2 = no pain; face 3-5 = pain). BPD included all athletes who reported faces 1 and 2 at M1 and faces 3 to 5 at M2. nBPD were all athletes who reported face 1 or 2 at both M1 and M2. Data was analyzed descriptively. Additionally, a Chi2 test was used to analyze gender- and sport-specific differences (p = 0.05). Results Thirty-two athletes were categorized as BPD (10\%). The gender difference was 5\% (m/f: 12\%/7\%) but did not show statistical significance (p = 0.15). The incidence of BP ranged between 6 and 15\% for the different sport categories. Game sports (15\%) showed the highest, and explosive strength sports (6\%) the lowest incidence. Anthropometrics or training characteristics did not significantly influence BPD (p = 0.14 gender to p = 0.90 sports; r2 = 0.0825). Conclusions BP incidence was lower in adolescent athletes compared to young non-athletes and even to the general adult population. Consequently, it can be concluded that high-performance sports do not lead to an additional increase in back pain incidence during early adolescence. Nevertheless, back pain prevention programs should be implemented into daily training routines for sport categories identified as showing high incidence rates.},
  language  = {en}
}
@inproceedings{KopinskiEngelCasseletal.2014,
  author    = {Kopinski, Stephan and Engel, Tilman and Cassel, Michael and Carlsohn, Anja and Mayer, Frank},
  title     = {Reliability of ultrasound measurements for subcutaneous adipose tissue in elite canoe athletes},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {46},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {539 -- 539},
  year      = {2014},
  language  = {en}
}
@misc{MuellerStollCasseletal.2017,
  author    = {M{\"u}ller, Steffen and Stoll, Josefine and Cassel, Michael and Mayer, Frank},
  title     = {Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-395261},
  pages     = {9},
  year      = {2017},
  abstract  = {In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 ± 1.3 y; 176 ± 11 cm; 68 ± 11 kg; 12.4 ± 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 ± 1.3 y; 174 ± 7 cm; 67 ± 8 kg; 14.9 ± 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [\%]) for all 12 single muscles were normalized to MIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP (p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3-1.9-fold) for BP (p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ (p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral (p = 0.031) and transverse muscles (p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment.},
  language  = {en}
}
@misc{BisiBalogunCasselMayer2017,
  author    = {Bisi-Balogun, Adebisi and Cassel, Michael and Mayer, Frank},
  title     = {Reliability of various measurement stations for determining plantar fascia thickness and echogenicity},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400615},
  pages     = {11},
  year      = {2017},
  abstract  = {This study aimed to determine the relative and absolute reliability of ultrasound (US) measurements of the thickness and echogenicity of the plantar fascia (PF) at different measurement stations along its length using a standardized protocol. Twelve healthy subjects (24 feet) were enrolled. The PF was imaged in the longitudinal plane. Subjects were assessed twice to evaluate the intra-rater reliability. A quantitative evaluation of the thickness and echogenicity of the plantar fascia was performed using Image J, a digital image analysis and viewer software. A sonography evaluation of the thickness and echogenicity of the PF showed a high relative reliability with an Intra class correlation coefficient of 0.88 at all measurement stations. However, the measurement stations for both the PF thickness and echogenicity which showed the highest intraclass correlation coefficient (ICCs) did not have the highest absolute reliability. Compared to other measurement stations, measuring the PF thickness at 3 cm distal and the echogenicity at a region of interest 1 cm to 2 cm distal from its insertion at the medial calcaneal tubercle showed the highest absolute reliability with the least systematic bias and random error. Also, the reliability was higher using a mean of three measurements compared to one measurement. To reduce discrepancies in the interpretation of the thickness and echogenicity measurements of the PF, the absolute reliability of the different measurement stations should be considered in clinical practice and research rather than the relative reliability with the ICC.},
  language  = {en}
}
@misc{CarlsohnScharhagRosenbergerCasseletal.2017,
  author    = {Carlsohn, Anja and Scharhag-Rosenberger, Friederike and Cassel, Michael and Mayer, Frank},
  title     = {Resting Metabolic Rate in Elite Rowers and Canoeists: Difference between Indirect Calorimetry and Prediction},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-399837},
  pages     = {6},
  year      = {2017},
  abstract  = {Background: Athletes may differ in their resting metabolic rate (RMR) from the general population. However, to estimate the RMR in athletes, prediction equations that have not been validated in athletes are often used. The purpose of this study was therefore to verify the applicability of commonly used RMR predictions for use in athletes. Methods: The RMR was measured by indirect calorimetry in 17 highly trained rowers and canoeists of the German national teams (BMI 24 ± 2 kg/m2, fat-free mass 69 ± 15 kg). In addition, the RMR was predicted using Cunningham (CUN) and Harris-Benedict (HB) equations. A two-way repeated measures ANOVA was calculated to test for differences between predicted and measured RMR (α = 0.05). The root mean square percentage error (RMSPE) was calculated and the Bland-Altman procedure was used to quantify the bias for each prediction. Results: Prediction equations significantly underestimated the RMR in males (p < 0.001). The RMSPE was calculated to be 18.4\% (CUN) and 20.9\% (HB) in the entire group. The bias was 133 kcal/24 h for CUN and 202 kcal/24 h for HB. Conclusions: Predictions significantly underestimate the RMR in male heavyweight endurance athletes but not in females. In athletes with a high fat-free mass, prediction equations might therefore not be applicable to estimate energy requirements. Instead, measurement of the resting energy expenditure or specific prediction equations might be needed for the individual heavyweight athlete.},
  language  = {en}
}
@misc{CasselIntziegianniRischetal.2017,
  author    = {Cassel, Michael and Intziegianni, Konstantina and Risch, Lucie and M{\"u}ller, Steffen and Engel, Tilman and Mayer, Frank},
  title     = {Physiological Tendon Thickness Adaptation in Adolescent Elite Athletes},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-403823},
  pages     = {8},
  year      = {2017},
  abstract  = {Increased Achilles (AT) and Patellar tendon (PT) thickness in adolescent athletes compared to non-athletes could be shown. However, it is unclear, if changes are of pathological or physiological origin due to training. The aim of this study was to determine physiological AT and PT thickness adaptation in adolescent elite athletes compared to non-athletes, considering sex and sport. In a longitudinal study design with two measurement days (M1/M2) within an interval of 3.2 ± 0.8 years, 131 healthy adolescent elite athletes (m/f: 90/41) out of 13 different sports and 24 recreationally active controls (m/f: 6/18) were included. Both ATs and PTs were measured at standardized reference points. Athletes were divided into 4 sport categories [ball (B), combat (C), endurance (E) and explosive strength sports (S)]. Descriptive analysis (mean ± SD) and statistical testing for group differences was performed (α = 0.05). AT thickness did not differ significantly between measurement days, neither in athletes (5.6 ± 0.7 mm/5.6 ± 0.7 mm) nor in controls (4.8 ± 0.4 mm/4.9 ± 0.5 mm, p > 0.05). For PTs, athletes presented increased thickness at M2 (M1: 3.5 ± 0.5 mm, M2: 3.8 ± 0.5 mm, p < 0.001). In general, males had thicker ATs and PTs than females (p < 0.05). Considering sex and sports, only male athletes from B, C, and S showed significant higher PT-thickness at M2 compared to controls (p ≤ 0.01). Sport-specific adaptation regarding tendon thickness in adolescent elite athletes can be detected in PTs among male athletes participating in certain sports with high repetitive jumping and strength components. Sonographic microstructural analysis might provide an enhanced insight into tendon material properties enabling the differentiation of sex and influence of different sports.},
  language  = {en}
}
@misc{KochCasselLinneetal.2017,
  author    = {Koch, Sarah and Cassel, Michael and Linne, Karsten and Mayer, Frank and Scharhag, J{\"u}rgen},
  title     = {ECG and echocardiographic findings in 10-15-year-old elite athletes},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-403186},
  pages     = {8},
  year      = {2017},
  abstract  = {Background: Data on electrocardiographic and echocardiographic pre-participation screening findings in paediatric athletes are limited. Methods and results: 10-15 year-old athletes (n = 343) were screened using electro- and echocardiography. The electrocardiogram (ECG) was normal in 220 (64\%), mildly abnormal in 108 (31\%), and distinctly abnormal in 15 (4\%) athletes. Echocardiographic upper reference limits (URL, 97.5 percentile) for the left ventricular (LV) wall thickness in 10-11-year-old boys and girls were 9-10 mm and 8-9 mm, respectively; in 12-13-year-old boys and girls 9-10 mm; and in 14-15-year-old boys and girls 10-11 mm and 9-10 mm, respectively. Three athletes were excluded from competitive sports: one for symptomatic Wolff-Parkinson-White syndrome with a normal echocardiogram; one for negative T-waves in V-1-V-4 and a dilated right ventricle by echocardiography suggestive of (arrhythmogenic) right ventricular disease; and one for normal ECG and biscupid aortic valve including an aneurysm of the ascending aorta detected by echocardiography. Related to echocardiographic findings, the sensitivity and specificity of the ECG to identify cardiovascular abnormalities was 38\% and 64\%, respectively. The ECG's positive-predictive and negative-predictive values were 13\% and 88\%, respectively. The numbers needed to screen and calculated costs were 172 for ECG ( 7049), 172 for echocardiography ( 11,530), and 114 combining ECG and echocardiography ( 9323). Conclusions: Compared to adults, paediatric athletes presented with fewer distinctly abnormal ECGs, and there was no gender difference in paediatric athletes' ECG-pattern distribution. A combination of ECG and echocardiography for pre-participation screening of paediatric athletes is superior to ECG alone but 30\% more costly.},
  language  = {en}
}
@article{MuellerStollMuelleretal.2017,
  author    = {M{\"u}ller, Steffen and Stoll, Josefine and Mueller, Juliane and Cassel, Michael and Mayer, Frank},
  title     = {Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain},
  series = {Frontiers in physiology},
  volume    = {8},
  journal   = {Frontiers in physiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2017.00274},
  pages     = {124 -- 132},
  year      = {2017},
  abstract  = {In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 +/- 1.3 y; 176 +/- 11 cm; 68 +/- 11 kg; 12.4 +/- 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 +/- 1.3 y; 174 +/- 7 cm; 67 +/- 8 kg; 14.9 +/- 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [\%]) for all 12 single muscles were normalized toMIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP (p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3-1.9-fold) for BP (p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ (p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral (p = 0.031) and transverse muscles (p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment.},
  language  = {en}
}
@inproceedings{CasselCarlsohnFroehlichetal.2013,
  author    = {Cassel, Michael and Carlsohn, Anja and Froehlich, Katja and Mayer, Frank},
  title     = {Achilles tendinopathy in adolescent athletes using ultrasound and clinical examination},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {45},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {350 -- 350},
  year      = {2013},
  language  = {en}
}
@misc{CasselMuellerMoseretal.2019,
  author    = {Cassel, Michael and M{\"u}ller, Juliane and Moser, Othmar and Strempler, Mares Elaine and Reso, Judith and Mayer, Frank},
  title     = {Orthopedic Injury Profiles in Adolescent Elite Athletes},
  series = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe},
  number    = {559},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-43495},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434953},
  pages     = {10},
  year      = {2019},
  abstract  = {Aim: The aim of the study was to identify common orthopedic sports injury profiles in adolescent elite athletes with respect to age, sex, and anthropometrics. Methods: A retrospective data analysis of 718 orthopedic presentations among 381 adolescent elite athletes from 16 different sports to a sports medical department was performed. Recorded data of history and clinical examination included area, cause and structure of acute and overuse injuries. Injury-events were analyzed in the whole cohort and stratified by age (11-14/15-17 years) and sex. Group differences were tested by chi-squared-tests. Logistic regression analysis was applied examining the influence of factors age, sex, and body mass index (BMI) on the outcome variables area and structure (a = 0.05). Results: Higher proportions of injury-events were reported for females (60\%) and athletes of the older age group (66\%) than males and younger athletes. The most frequently injured area was the lower extremity (47\%) followed by the spine (30.5\%) and the upper extremity (12.5\%). Acute injuries were mainly located at the lower extremity (74.5\%), while overuse injuries were predominantly observed at the lower extremity (41\%) as well as the spine (36.5\%). Joints (34\%), muscles (22\%), and tendons (21.5\%) were found to be the most often affected structures. The injured structures were different between the age groups (p = 0.022), with the older age group presenting three times more frequent with ligament pathology events (5.5\%/2\%) and less frequent with bony problems (11\%/20.5\%) than athletes of the younger age group. The injured area differed between the sexes (p = 0.005), with males having fewer spine injury-events (25.5\%/34\%) but more upper extremity injuries (18\%/9\%) than females. Regression analysis showed statistically significant influence for BMI (p = 0.002) and age (p = 0.015) on structure, whereas the area was significantly influenced by sex (p = 0.005). Conclusion: Events of soft-tissue overuse injuries are the most common reasons resulting in orthopedic presentations of adolescent elite athletes. Mostly, the lower extremity and the spine are affected, while sex and age characteristics on affected area and structure must be considered. Therefore, prevention strategies addressing the injury-event profiles should already be implemented in early adolescence taking age, sex as well as injury entity into account.},
  language  = {en}
}
@article{CasselIntziegianniRischetal.2017,
  author    = {Cassel, Michael and Intziegianni, Konstantina and Risch, Lucie and Mueller, Steffen and Engel, Tilman and Mayer, Frank},
  title     = {Physiological Tendon Thickness Adaptation in Adolescent Elite Athletes: A Longitudinal Study},
  series = {Frontiers in physiology},
  volume    = {8},
  journal   = {Frontiers in physiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2017.00795},
  pages     = {599 -- 611},
  year      = {2017},
  abstract  = {Increased Achilles (AT) and Patellar tendon (PT) thickness in adolescent athletes compared to non-athletes could be shown. However, it is unclear, if changes are of pathological or physiological origin due to training. The aim of this study was to determine physiological AT and PT thickness adaptation in adolescent elite athletes compared to non-athletes, considering sex and sport. In a longitudinal study design with two measurement days (M1/M2) within an interval of 3.2 +/- 0.8 years, 131 healthy adolescent elite athletes (m/f: 90/41) out of 13 different sports and 24 recreationally active controls (m/f: 6/18) were included. Both ATs and PTs were measured at standardized reference points. Athletes were divided into 4 sport categories [ball (B), combat (C), endurance (E) and explosive strength sports (S)]. Descriptive analysis (mean SD) and statistical testing for group differences was performed (cy = 0.05). AT thickness did not differ significantly between measurement days, neither in athletes (5.6 +/- 0.7 mm/5.6 +/- 0.7 mm) nor in controls (4.8 +/- 0.4 mm/4.9 +/- 0.5 mm, p > 0.05). For PTs, athletes presented increased thickness at M2 (Ml: 3.5 +/- 0.5 mm, M2: 3.8 +/- 0.5 mm, p < 0.001). In general, males had thicker ATs and PTs than females (p < 0.05). Considering sex and sports, only male athletes from B, C, and S showed significant higher PT-thickness at M2 compared to controls (p <= 0.01). Sport-specific adaptation regarding tendon thickness in adolescent elite athletes can be detected in PTs among male athletes participating in certain sports with high repetitive jumping and strength components. Sonographic microstructural analysis might provide an enhanced insight into tendon material properties enabling the differentiation of sex and influence of different sports.},
  language  = {en}
}
@misc{RischMayerCassel2021,
  author    = {Risch, Lucie and Mayer, Frank and Cassel, Michael},
  title     = {Doppler flow response following running exercise differs between healthy and tendinopathic Achilles tendons},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-52136},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-521367},
  pages     = {12},
  year      = {2021},
  abstract  = {Background: The relationship between exercise-induced intratendinous blood flow (IBF) and tendon pathology or training exposure is unclear. Objective: This study investigates the acute effect of running exercise on sonographic detectable IBF in healthy and tendinopathic Achilles tendons (ATs) of runners and recreational participants. Methods: 48 participants (43 ± 13 years, 176 ± 9 cm, 75 ± 11 kg) performed a standardized submaximal 30-min constant load treadmill run with Doppler ultrasound "Advanced dynamic flow" examinations before (Upre) and 5, 30, 60, and 120 min (U5-U120) afterward. Included were runners (>30 km/week) and recreational participants (<10 km/week) with healthy (Hrun, n = 10; Hrec, n = 15) or tendinopathic (Trun, n = 13; Trec, n = 10) ATs. IBF was assessed by counting number [n] of intratendinous vessels. IBF data are presented descriptively (\%, median [minimum to maximum range] for baseline-IBF and IBF-difference post-exercise). Statistical differences for group and time point IBF and IBF changes were analyzed with Friedman and Kruskal-Wallis ANOVA (α = 0.05). Results: At baseline, IBF was detected in 40\% (3 [1-6]) of Hrun, in 53\% (4 [1-5]) of Hrec, in 85\% (3 [1-25]) of Trun, and 70\% (10 [2-30]) of Trec. At U5 IBF responded to exercise in 30\% (3 [-1-9]) of Hrun, in 53\% (4 [-2-6]) of Hrec, in 70\% (4 [-10-10]) of Trun, and in 80\% (5 [1-10]) of Trec. While IBF in 80\% of healthy responding ATs returned to baseline at U30, IBF remained elevated until U120 in 60\% of tendinopathic ATs. Within groups, IBF changes from Upre-U120 were significant for Hrec (p < 0.01), Trun (p = 0.05), and Trec (p < 0.01). Between groups, IBF changes in consecutive examinations were not significantly different (p > 0.05) but IBF-level was significantly higher at all measurement time points in tendinopathic versus healthy ATs (p < 0.05). Conclusion: Irrespective of training status and tendon pathology, running leads to an immediate increase of IBF in responding tendons. This increase occurs shortly in healthy and prolonged in tendinopathic ATs. Training exposure does not alter IBF occurrence, but IBF level is elevated in tendon pathology. While an immediate exercise-induced IBF increase is a physiological response, prolonged IBF is considered a pathological finding associated with Achilles tendinopathy.},
  language  = {en}
}
@article{KimLinHenschkeetal.2023,
  author    = {Kim, MyoungHwee and Lin, Chiao-I and Henschke, Jakob and Quarmby, Andrew James and Engel, Tilman and Cassel, Michael},
  title     = {Effects of exercise treatment on functional outcome parameters in mid-portion achilles tendinopathy},
  series = {Frontiers in Sports and Active Living},
  volume    = {5},
  journal   = {Frontiers in Sports and Active Living},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {2624-9367},
  doi       = {10.3389/fspor.2023.1144484},
  pages     = {12},
  year      = {2023},
  abstract  = {Exercise interventions are evident in the treatment of mid-portion Achilles tendinopathy (AT). However, there is still a lack of knowledge concerning the effect of different exercise treatments on improving a specific function (e.g., strength) in this population. Thus, this study aimed to systematically review the effect of exercise treatments on different functional outcomes in mid-portion AT. An electronic database of Pubmed, Web of Science, and Cochrane Central Register of Controlled Trials were searched from inception to 21 February 2023. Studies that investigated changes in plantar flexor function with exercise treatments were considered in mid-portion AT. Only randomized controlled trials (RCTs) and clinical controlled trials (CCTs) were included. Functional outcomes were classified by kinetic (e.g., strength), kinematic [e.g., ankle range of motion (ROM)], and sensorimotor (e.g., balance index) parameters. The types of exercise treatments were classified into eccentric, concentric, and combined (eccentric plus concentric) training modes. Quality assessment was appraised using the Physiotherapy Evidence Database scale for RCTs, and the Joanna Briggs Institute scale for CCTs. The search yielded 2,260 records, and a total of ten studies were included. Due to the heterogeneity of the included studies, a qualitative synthesis was performed. Eccentric training led to improvements in power outcomes (e.g., height of countermovement jump), and in strength outcomes (e.g., peak torque). Concentric training regimens showed moderate enhanced power outcomes. Moreover, one high-quality study showed an improvement in the balance index by eccentric training, whereas the application of concentric training did not. Combined training modalities did not lead to improvements in strength and power outcomes. Plantarflexion and dorsiflexion ROM measures did not show relevant changes by the exercise treatments. In conclusion, eccentric training is evident in improving strength outcomes in AT patients. Moreover, it shows moderate evidence improvements in power and the sensorimotor parameter "balance index". Concentric training presents moderate evidence in the power outcomes and can therefore be considered as an alternative to improve this function. Kinematic analysis of plantarflexion and dorsiflexion ROM might not be useful in AT people. This study expands the knowledge what types of exercise regimes should be considered to improve the functional outcomes in AT.},
  language  = {en}
}
@misc{MuellerMuellerStolletal.2017,
  author    = {M{\"u}ller, Steffen and M{\"u}ller, Juliane and Stoll, Josefine and Prieske, Olaf and Cassel, Michael and Mayer, Frank},
  title     = {Incidence of back pain in adolescent athletes},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-101874},
  pages     = {5},
  year      = {2017},
  abstract  = {Background Recently, the incidence rate of back pain (BP) in adolescents has been reported at 21\%. However, the development of BP in adolescent athletes is unclear. Hence, the purpose of this study was to examine the incidence of BP in young elite athletes in relation to gender and type of sport practiced. Methods Subjective BP was assessed in 321 elite adolescent athletes (m/f 57\%/43\%; 13.2 ± 1.4 years; 163.4 ± 11.4 cm; 52.6 ± 12.6 kg; 5.0 ± 2.6 training yrs; 7.6 ± 5.3 training h/week). Initially, all athletes were free of pain. The main outcome criterion was the incidence of back pain [\%] analyzed in terms of pain development from the first measurement day (M1) to the second measurement day (M2) after 2.0 ± 1.0 year. Participants were classified into athletes who developed back pain (BPD) and athletes who did not develop back pain (nBPD). BP (acute or within the last 7 days) was assessed with a 5-step face scale (face 1-2 = no pain; face 3-5 = pain). BPD included all athletes who reported faces 1 and 2 at M1 and faces 3 to 5 at M2. nBPD were all athletes who reported face 1 or 2 at both M1 and M2. Data was analyzed descriptively. Additionally, a Chi2 test was used to analyze gender- and sport-specific differences (p = 0.05). Results Thirty-two athletes were categorized as BPD (10\%). The gender difference was 5\% (m/f: 12\%/7\%) but did not show statistical significance (p = 0.15). The incidence of BP ranged between 6 and 15\% for the different sport categories. Game sports (15\%) showed the highest, and explosive strength sports (6\%) the lowest incidence. Anthropometrics or training characteristics did not significantly influence BPD (p = 0.14 gender to p = 0.90 sports; r2 = 0.0825). Conclusions BP incidence was lower in adolescent athletes compared to young non-athletes and even to the general adult population. Consequently, it can be concluded that high-performance sports do not lead to an additional increase in back pain incidence during early adolescence. Nevertheless, back pain prevention programs should be implemented into daily training routines for sport categories identified as showing high incidence rates.},
  language  = {en}
}
@article{ScharhagRosenbergerCarlsohnCasseletal.2011,
  author    = {Scharhag-Rosenberger, Friederike and Carlsohn, Anja and Cassel, Michael and Mayer, Frank and Scharhag, J{\"u}rgen},
  title     = {How to test maximal oxygen uptake a study on timing and testing procedure of a supramaximal verification test},
  series = {Applied physiology, nutrition, and metabolism = Physiologie appliqu{\´e}e, nutrition et m{\´e}tabolisme},
  volume    = {36},
  journal   = {Applied physiology, nutrition, and metabolism = Physiologie appliqu{\´e}e, nutrition et m{\´e}tabolisme},
  number    = {1},
  publisher = {NRC Research Press},
  address   = {Ottawa},
  issn      = {1715-5312},
  doi       = {10.1139/H10-099},
  pages     = {153 -- 160},
  year      = {2011},
  abstract  = {On utilise de plus en plus les tests de verification pour confirmer l'atteinte du consommation d'oxygene maximale (VO(2 max)). Toutefois, le moment et les methodes d'evaluation varient d'un groupe de travail a l'autre. Les objectifs de cette etude sont de constater si on peut administrer un test de verification apres un test d'effort progressif ou s'il est preferable de le faire une autre journee et si on peut determiner le VO(2 max) tout de meme lors de la premiere seance chez des sujets ne repondant pas au critere de verification. Quarante sujets (age, 24 +/- 4 ans; VO(2 max), 50 +/- 7 mL center dot min(-1)center dot kg(-1)) participent a un test d'effort progressif sur tapis roulant et, 10 min plus tard, a un test de verification (VerifDay1) a 110 \% de la velocite maximale (v(max)). Le critere de verification est un VO(2) de pointe au VerifDay1 < 5,5 \% a la valeur retenue au test d'effort progressif. Les sujets ne repondant pas au critere de verification passent un autre test de verification, mais a 115 \% du VerifDay1', et ce, 10 min plus tard pour confirmer le VO(2) de pointe du VerifDay1 en tant que VO(2 max). Tous les autres sujets repassent le VerifDay1 a un jour different (VerifDay2). Six sujets sur quarante ne repondent pas au critere de verification. Chez quatre d'entre eux, on confirme l'atteinte du VO(2 max) au VerifDay1'. Le VO(2) de pointe au VerifDay1 est equivalent a celui du VerifDay2 (3722 +/- 991 mL center dot min(-1) comparativement a 3752 +/- 995 mL center dot min(-1), p = 0,56), mais le temps jusqu'a l'epuisement est significativement plus long au VerifDay2 (2:06 +/- 0:22 min:s comparativement a 2:42 +/- 0:38 min:s, p < 0,001, n = 34). Le VO(2) de pointe obtenu au test de verification ne semble pas conditionne par un test d'effort progressif maximal prealable. On peut donc realiser le test d'effort progressif et le test de verification lors de la meme seance d'evaluation. Chez presque tous les individus ne repondant pas au critere de verification, on peut determiner le VO(2 max) au moyen d'un autre test de verification plus intense.},
  language  = {en}
}
@article{KoenigCasselIntziegiannietal.2014,
  author    = {K{\"o}nig, Niklas and Cassel, Michael and Intziegianni, Konstantina and Mayer, Frank},
  title     = {Inter-rater reliability and measurement error of sonographic muscle architecture assessments},
  series = {Journal of ultrasound in medicine},
  volume    = {33},
  journal   = {Journal of ultrasound in medicine},
  number    = {5},
  publisher = {American Institute of Ultrasound in Medicine},
  address   = {Laurel},
  issn      = {0278-4297},
  doi       = {10.7863/ultra.33.5.769},
  pages     = {769 -- 777},
  year      = {2014},
  abstract  = {Objectives-Sonography of muscle architecture provides physicians and researchers with information about muscle function and muscle-related disorders. Inter-rater reliability is a crucial parameter in daily clinical routines. The aim of this study was to assess the inter-rater reliability of sonographic muscle architecture assessments and quantification of errors that arise from inconsistent probe positioning and image interpretation. Results-Inter-rater reliability was good overall (ICC, 0.77-0.90; IRV, 9.0\%-13.4\%; bias LoA, 0.2 +/- 0.2-1.7 +/- 3.0). Superior and inferior pennation angles showed high systematic bias and LoA in all setups, ranging from 2.0 degrees +/- 2.2 degrees to 3.4 degrees +/- 4.1 degrees. The highest IRV was found for muscle thickness (13.4\%). "When the probe position was standardized, the SEM for muscle thickness decreased from 0.1 to 0.05 cm. Conclusions-Sonographic examination of muscle architecture of the medial gastrocnemius has good to high reliability. In contrast to pennation angle measurements, length measurements can be improved by standardization of the probe position.},
  language  = {en}
}
@misc{CarlsohnCasselLinneetal.2010,
  author    = {Carlsohn, Anja and Cassel, Michael and Linn{\´e}, Karsten and Mayer, Frank},
  title     = {How much is too much?},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {515},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-41291},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-412910},
  pages     = {5},
  year      = {2010},
  abstract  = {Although dietary nutrient intake is often adequate, nutritional supplement use is common among elite athletes. However, high-dose supplements or the use of multiple supplements may exceed the recommended daily allowance (RDA) of particular nutrients or even result in a daily intake above tolerable upper limits (UL). The present case report presents nutritional intake data and supplement use of a highly trained male swimmer competing at international level. Habitual energy and micronutrient intake were analysed by 3 d dietary reports. Supplement use and dosage were assessed, and total amount of nutrient supply was calculated. Micronutrient intake was evaluated based on RDA and UL as presented by the European Scientific Committee on Food, and maximum permitted levels in supplements (MPL) are given. The athlete's diet provided adequate micronutrient content well above RDA except for vitamin D. Simultaneous use of ten different supplements was reported, resulting in excess intake above tolerable UL for folate, vitamin E and Zn. Additionally, daily supplement dosage was considerably above MPL for nine micronutrients consumed as artificial products. Risks and possible side effects of exceeding UL by the athlete are discussed. Athletes with high energy intake may be at risk of exceeding UL of particular nutrients if multiple supplements are added. Therefore, dietary counselling of athletes should include assessment of habitual diet and nutritional supplement intake. Educating athletes to balance their diets instead of taking supplements might be prudent to prevent health risks that may occur with long-term excess nutrient intake.},
  language  = {en}
}
@misc{RischStollSchomoelleretal.2021,
  author    = {Risch, Lucie and Stoll, Josefine and Schom{\"o}ller, Anne and Engel, Tilman and Mayer, Frank and Cassel, Michael},
  title     = {Intraindividual Doppler Flow Response to Exercise Differs Between Symptomatic and Asymptomatic Achilles Tendons},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-54286},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-542865},
  pages     = {1 -- 8},
  year      = {2021},
  abstract  = {Objective: This study investigated intraindividual differences of intratendinous blood flow (IBF) in response to running exercise in participants with Achilles tendinopathy. Design: This is a cross-sectional study. Setting: The study was conducted at the University Outpatient Clinic. Participants: Sonographic detectable intratendinous blood flow was examined in symptomatic and contralateral asymptomatic Achilles tendons of 19 participants (42 ± 13 years, 178 ± 10 cm, 76 ± 12 kg, VISA-A 75 ± 16) with clinically diagnosed unilateral Achilles tendinopathy and sonographic evident tendinosis. Intervention: IBF was assessed using Doppler ultrasound "Advanced Dynamic Flow" before (Upre) and 5, 30, 60, and 120 min (U5-U120) after a standardized submaximal constant load run. Main Outcome Measure: IBF was quantified by counting the number (n) of vessels in each tendon. Results: At Upre, IBF was higher in symptomatic compared with asymptomatic tendons [mean 6.3 (95\% CI: 2.8-9.9) and 1.7 (0.4-2.9), p < 0.01]. Overall, 63\% of symptomatic and 47\% of asymptomatic Achilles tendons responded to exercise, whereas 16 and 11\% showed persisting IBF and 21 and 42\% remained avascular throughout the investigation. At U5, IBF increased in both symptomatic and asymptomatic tendons [difference to baseline: 2.4 (0.3-4.5) and 0.9 (0.5-1.4), p = 0.05]. At U30 to U120, IBF was still increased in symptomatic but not in asymptomatic tendons [mean difference to baseline: 1.9 (0.8-2.9) and 0.1 (-0.9 to 1.2), p < 0.01]. Conclusion: Irrespective of pathology, 47-63\% of Achilles tendons responded to exercise with an immediate acute physiological IBF increase by an average of one to two vessels ("responders"). A higher amount of baseline IBF (approximately five vessels) and a prolonged exercise-induced IBF response found in symptomatic ATs indicate a pain-associated altered intratendinous "neovascularization."},
  language  = {en}
}
@article{WojcinskiCasselFarrokhetal.2012,
  author    = {Wojcinski, Sebastian and Cassel, Michael and Farrokh, Andre and Soliman, Amr A. and Hille, Ursula and Schmidt, Werner and Degenhardt, Friedrich and Hillemanns, Peter},
  title     = {Variations in the elasticity of breast tissue during the menstrual cycle determined by real-time sonoelastography},
  series = {Journal of ultrasound in medicine},
  volume    = {31},
  journal   = {Journal of ultrasound in medicine},
  number    = {1},
  publisher = {American Institute of Ultrasound in Medicine},
  address   = {Laurel},
  issn      = {0278-4297},
  pages     = {63 -- 72},
  year      = {2012},
  abstract  = {Objectives-The purpose of this study was to determine the dependence of breast tissue elasticity on the menstrual cycle of healthy volunteers by means of real-time sonoelastography. Methods-Twenty-two healthy volunteers (aged 18-33 years) were examined once weekly during two consecutive menstrual cycles using sonoelastography. Group 1 (n = 10) was not taking hormonal medication; group 2 (n = 12) was taking oral contraceptives. Results-The breast parenchyma appeared softer than the dermis and harder than the adipose tissue, and elasticity varied over the menstrual cycle and between groups. Group 1 (no hormone intake) showed continuously increasing elasticity with relatively soft breast parenchyma in the menstrual and follicular phases and harder parenchyma in the luteal phase (P = .012). Group 2 (oral contraceptives) showed no statistically significant changes in breast parenchymal elasticity according to sonoelastography. The parenchyma was generally softer in group 1 compared with group 2 throughout the menstrual cycle (P = .033). The dermis, the subcutaneous adipose tissue, and the pectoralis major muscle showed no changes in elasticity. Comparison of measurements made during the first and the second menstrual cycles showed similar patterns of elasticity in both groups. Conclusions-Sonoelastography is a reproducible method that can be used to determine the dependence of breast parenchyma elasticity on the menstrual cycle and on the intake of hormonal contraceptives.},
  language  = {en}
}
@article{WojcinskiDupontSchmidtetal.2012,
  author    = {Wojcinski, Sebastian and Dupont, Jennifer and Schmidt, Werner and Cassel, Michael and Hillemanns, Peter},
  title     = {Real-time ultrasound elastography in 180 axillary lymph nodes elasticity distribution in healthy lymph nodes and prediction of breast cancer metastases},
  series = {BMC medical imaging},
  volume    = {12},
  journal   = {BMC medical imaging},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1471-2342},
  doi       = {10.1186/1471-2342-12-35},
  pages     = {10},
  year      = {2012},
  abstract  = {Background: To determine the general appearance of normal axillary lymph nodes (LNs) in real-time tissue sonoelastography and to explore the method's potential value in the prediction of LN metastases. Methods: Axillary LNs in healthy probands (n=165) and metastatic LNs in breast cancer patients (n=15) were examined with palpation, B-mode ultrasound, Doppler and sonoelastography (assessment of the elasticity of the cortex and the medulla). The elasticity distributions were compared and sensitivity (SE) and specificity (SP) were calculated. In an exploratory analysis, positive and negative predictive values (PPV, NPV) were calculated based upon the estimated prevalence of LN metastases in different risk groups. Results: In the elastogram, the LN cortex was significantly harder than the medulla in both healthy (p=0.004) and metastatic LNs (p=0.005). Comparing healthy and metastatic LNs, there was no difference in the elasticity distribution of the medulla (p=0.281), but we found a significantly harder cortex in metastatic LNs (p=0.006). The SE of clinical examination, B-mode ultrasound, Doppler ultrasound and sonoelastography was revealed to be 13.3\%, 40.0\%, 14.3\% and 60.0\%, respectively, and SP was 88.4\%, 96.8\%, 95.6\% and 79.6\%, respectively. The highest SE was achieved by the disjunctive combination of B-mode and elastographic features (cortex >3mm in B-mode or blue cortex in the elastogram, SE=73.3\%). The highest SP was achieved by the conjunctive combination of B-mode ultrasound and elastography (cortex >3mm in B-mode and blue cortex in the elastogram, SP=99.3\%). Conclusions: Sonoelastography is a feasible method to visualize the elasticity distribution of LNs. Moreover, sonoelastography is capable of detecting elasticity differences between the cortex and medulla, and between metastatic and healthy LNs. Therefore, sonoelastography yields additional information about axillary LN status and can improve the PPV, although this method is still experimental.},
  language  = {en}
}
@misc{QuarmbyMoennigMugeleetal.2023,
  author    = {Quarmby, Andrew James and M{\"o}nnig, Jamal and Mugele, Hendrik and Henschke, Jakob and Kim, MyoungHwee and Cassel, Michael and Engel, Tilman},
  title     = {Biomechanics and lower limb function are altered in athletes and runners with achilles tendinopathy compared with healthy controls: A systematic review},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {830},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-58760},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-587603},
  pages     = {20},
  year      = {2023},
  abstract  = {Achilles tendinopathy (AT) is a debilitating injury in athletes, especially for those engaged in repetitive stretch-shortening cycle activities. Clinical risk factors are numerous, but it has been suggested that altered biomechanics might be associated with AT. No systematic review has been conducted investigating these biomechanical alterations in specifically athletic populations. Therefore, the aim of this systematic review was to compare the lower-limb biomechanics of athletes with AT to athletically matched asymptomatic controls. Databases were searched for relevant studies investigating biomechanics during gait activities and other motor tasks such as hopping, isolated strength tasks, and reflex responses. Inclusion criteria for studies were an AT diagnosis in at least one group, cross-sectional or prospective data, at least one outcome comparing biomechanical data between an AT and healthy group, and athletic populations. Studies were excluded if patients had Achilles tendon rupture/surgery, participants reported injuries other than AT, and when only within-subject data was available.. Effect sizes (Cohen's d) with 95\% confidence intervals were calculated for relevant outcomes. The initial search yielded 4,442 studies. After screening, twenty studies (775 total participants) were synthesised, reporting on a wide range of biomechanical outcomes. Females were under-represented and patients in the AT group were three years older on average. Biomechanical alterations were identified in some studies during running, hopping, jumping, strength tasks and reflex activity. Equally, several biomechanical variables studied were not associated with AT in included studies, indicating a conflicting picture. Kinematics in AT patients appeared to be altered in the lower limb, potentially indicating a pattern of "medial collapse". Muscular activity of the calf and hips was different between groups, whereby AT patients exhibited greater calf electromyographic amplitudes despite lower plantar flexor strength. Overall, dynamic maximal strength of the plantar flexors, and isometric strength of the hips might be reduced in the AT group. This systematic review reports on several biomechanical alterations in athletes with AT. With further research, these factors could potentially form treatment targets for clinicians, although clinical approaches should take other contributing health factors into account. The studies included were of low quality, and currently no solid conclusions can be drawn.},
  language  = {en}
}
@article{QuarmbyMoennigMugeleetal.2023,
  author    = {Quarmby, Andrew James and M{\"o}nnig, Jamal and Mugele, Hendrik and Henschke, Jakob and Kim, MyoungHwee and Cassel, Michael and Engel, Tilman},
  title     = {Biomechanics and lower limb function are altered in athletes and runners with achilles tendinopathy compared with healthy controls: A systematic review},
  series = {Frontiers in Sports and Active Living},
  journal   = {Frontiers in Sports and Active Living},
  publisher = {Frontiers},
  address   = {Lausanne, Schweiz},
  issn      = {2624-9367},
  doi       = {10.3389/fspor.2022.1012471},
  pages     = {20},
  year      = {2023},
  abstract  = {Achilles tendinopathy (AT) is a debilitating injury in athletes, especially for those engaged in repetitive stretch-shortening cycle activities. Clinical risk factors are numerous, but it has been suggested that altered biomechanics might be associated with AT. No systematic review has been conducted investigating these biomechanical alterations in specifically athletic populations. Therefore, the aim of this systematic review was to compare the lower-limb biomechanics of athletes with AT to athletically matched asymptomatic controls. Databases were searched for relevant studies investigating biomechanics during gait activities and other motor tasks such as hopping, isolated strength tasks, and reflex responses. Inclusion criteria for studies were an AT diagnosis in at least one group, cross-sectional or prospective data, at least one outcome comparing biomechanical data between an AT and healthy group, and athletic populations. Studies were excluded if patients had Achilles tendon rupture/surgery, participants reported injuries other than AT, and when only within-subject data was available.. Effect sizes (Cohen's d) with 95\% confidence intervals were calculated for relevant outcomes. The initial search yielded 4,442 studies. After screening, twenty studies (775 total participants) were synthesised, reporting on a wide range of biomechanical outcomes. Females were under-represented and patients in the AT group were three years older on average. Biomechanical alterations were identified in some studies during running, hopping, jumping, strength tasks and reflex activity. Equally, several biomechanical variables studied were not associated with AT in included studies, indicating a conflicting picture. Kinematics in AT patients appeared to be altered in the lower limb, potentially indicating a pattern of "medial collapse". Muscular activity of the calf and hips was different between groups, whereby AT patients exhibited greater calf electromyographic amplitudes despite lower plantar flexor strength. Overall, dynamic maximal strength of the plantar flexors, and isometric strength of the hips might be reduced in the AT group. This systematic review reports on several biomechanical alterations in athletes with AT. With further research, these factors could potentially form treatment targets for clinicians, although clinical approaches should take other contributing health factors into account. The studies included were of low quality, and currently no solid conclusions can be drawn.},
  language  = {en}
}
@phdthesis{Cassel2021,
  author    = {Cassel, Michael},
  title     = {Klinische Analyse der physiologischen und pathologischen Sehnenadaptation an sportliche Belastung},
  year      = {2021},
  language  = {de}
}
@article{BaurHirschmuellerCasseletal.2010,
  author    = {Baur, Heiner and Hirschm{\"u}ller, Anja and Cassel, Michael and M{\"u}ller, Steffen and Mayer, Frank},
  title     = {Gender-specific neuromuscular activity of the M. peroneus longus in healthy runners : a descriptive laboratory study},
  issn      = {0268-0033},
  doi       = {10.1016/j.clinbiomech.2010.06.009},
  year      = {2010},
  abstract  = {Background: Gender-specific neuromuscular activity for the ankle (e.g., peroneal muscle) is currently not known. This knowledge may contribute to the understanding of overuse injury mechanisms. The purpose was therefore to analyse the neuromuscular activity of the peroneal muscle in healthy runners. Methods: Fifty-three male and 54 female competitive runners were tested on a treadmill at 3.33 m s(-1). Neuromuscular activity of the M. peroneus longus was measured by electromyography and analysed in the time domain (onset of activation, time of maximum of activation, total time of activation) in \% of stride time in relation to touchdown (= 1.0). Additionally, mean amplitudes for the gait cycle phases preactivation, weight acceptance and push-off were calculated and normalised to the mean activity of the entire gait cycle. Findings: Onset of activation (mean; female: 0.86/male: 0.90, p<0.0001) and time of maximum of activation (female: 1.13/male: 1.16, p<0.0001) occurred earlier in female compared to male and the total time of activation was longer in women (female: 0.42/male: 0.39, p=0.0036). In preactivation, women showed higher amplitudes (+ 21\%) compared to men (female: 1.16/male: 0.92, p<0.0001). Activity during weight acceptance (female: 2.26/male: 2.41, p = 0.0039) and push-off (female: 0.93/male: 1.07, p = 0.0027) were higher in men. Interpretation: Activation strategies of the peroneal muscle appear to be gender-specific. Higher preactivation amplitudes in females indicate a different neuromuscular control in anticipation of touchdown ("pre-programmed activity"). These data may help interpret epidemiologically reported differences between genders in overuse injury frequency and localisation.},
  language  = {en}
}
@inproceedings{WochatzCasselKoenigetal.2013,
  author    = {Wochatz, Monique and Cassel, Michael and K{\"o}nig, Niklas and Fr{\"o}hlich, Katja and Mayer, Frank},
  title     = {Intra- and inter-observer variability of a retrospective analysis of achilles tendon ultrasound scans},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {45},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {239 -- 239},
  year      = {2013},
  language  = {en}
}
@inproceedings{IntziegianniCasselKoenigetal.2013,
  author    = {Intziegianni, Konstantina and Cassel, Michael and K{\"o}nig, Niklas and Mayer, Frank},
  title     = {Reliability of variables defining mechanical and material properties of the achilles tendon},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {45},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {238 -- 239},
  year      = {2013},
  language  = {en}
}
@inproceedings{IntziegianniCasselMuelleretal.2012,
  author    = {Intziegianni, Konstantina and Cassel, Michael and M{\"u}ller, Steffen and Mayer, Frank},
  title     = {Ultrasound evaluation of the patellar tendon cross-sectional area and its relation to maximum force},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {44},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {714 -- 714},
  year      = {2012},
  language  = {en}
}
@article{CasselCarlsohnFroehlichetal.2016,
  author    = {Cassel, Michael and Carlsohn, Anja and Fr{\"o}hlich, Katja and John, Mareike and Riegels, N. and Mayer, Frank},
  title     = {Tendon Adaptation to Sport-specific Loading in Adolescent Athletes},
  series = {International journal of sports medicine},
  volume    = {37},
  journal   = {International journal of sports medicine},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/s-0035-1559772},
  pages     = {159 -- 164},
  year      = {2016},
  abstract  = {Tendon adaptation due to mechanical loading is controversially discussed. However, data concerning the development of tendon thickness in adolescent athletes is sparse. The purpose of this study was to examine possible differences in Achilles (AT) and patellar tendon (PT) thickness in adolescent athletes while considering age, gender and sport-specific loading. In 500 adolescent competitive athletes of 16 different sports and 40 recreational controls both ATs and PTs were sonographically measured. Subjects were divided into 2 age groups (< 13; \&\#8805; 13 years) and 6 sport type categories (ball, combat, and water sports, combined disciplines, cycling, controls). In addition, 3 risk groups (low, moderate, high) were created according to the athlete's risk of developing tendinopathy. AT and PT thickness did not significantly differ between age groups (AT/PT:<13: 5.4±0.7 mm/3.6±0.5 mm;\&\#8805;13: 5.3±0.7 mm/3.6±0.5 mm). In both age groups males presented higher tendon thickness than females (p<0.001). AT thickness was highest in ball sports/cyclists and lowest in controls (p\&\#8804;0.002). PT thickness was greatest in water sports and lowest in controls (p=0.02). High risk athletes presented slightly higher AT thickness compared to the low risk group (p=0.03). Increased AT and PT thickness in certain sport types compared to controls supports the hypothesis of structural tendon adaptation due to sport-specific loading.},
  language  = {en}
}
@article{CarlsohnCasselLinneetal.2011,
  author    = {Carlsohn, Anja and Cassel, Michael and Linne, Karsten and Mayer, Frank},
  title     = {How much is too much? - a case report of nutritional supplement use of a high-performance athlete},
  series = {The British journal of nutrition : an international journal devoted to the science of human and animal nutrition},
  volume    = {105},
  journal   = {The British journal of nutrition : an international journal devoted to the science of human and animal nutrition},
  number    = {12},
  publisher = {Cambridge Univ. Press},
  address   = {Cambridge},
  issn      = {0007-1145},
  doi       = {10.1017/S0007114510005556},
  pages     = {1724 -- 1728},
  year      = {2011},
  abstract  = {Although dietary nutrient intake is often adequate, nutritional supplement use is common among elite athletes. However, high-dose supplements or the use of multiple supplements may exceed the recommended daily allowance (RDA) of particular nutrients or even result in a daily intake above tolerable upper limits (UL). The present case report presents nutritional intake data and supplement use of a highly trained male swimmer competing at international level. Habitual energy and micronutrient intake were analysed by 3 d dietary reports. Supplement use and dosage were assessed, and total amount of nutrient supply was calculated. Micronutrient intake was evaluated based on RDA and UL as presented by the European Scientific Committee on Food, and maximum permitted levels in supplements (MPL) are given. The athlete's diet provided adequate micronutrient content well above RDA except for vitamin D. Simultaneous use of ten different supplements was reported, resulting in excess intake above tolerable UL for folate, vitamin E and Zn. Additionally, daily supplement dosage was considerably above MPL for nine micronutrients consumed as artificial products. Risks and possible side effects of exceeding UL by the athlete are discussed. Athletes with high energy intake may be at risk of exceeding UL of particular nutrients if multiple supplements are added. Therefore, dietary counselling of athletes should include assessment of habitual diet and nutritional supplement intake. Educating athletes to balance their diets instead of taking supplements might be prudent to prevent health risks that may occur with long-term excess nutrient intake.},
  language  = {en}
}
@misc{MayerScharhagRosenbergerCarlsohnetal.2011,
  author    = {Mayer, Frank and Scharhag-Rosenberger, Friederike and Carlsohn, Anja and Cassel, Michael and M{\"u}ller, Steffen and Scharhag, J{\"u}rgen},
  title     = {The intensity and effects of strength training in the elderly},
  series = {Deutsches {\"A}rzteblatt international : a weekly online journal of clinical medicine and public health},
  volume    = {108},
  journal   = {Deutsches {\"A}rzteblatt international : a weekly online journal of clinical medicine and public health},
  number    = {21},
  publisher = {Dt. {\"A}rzte-Verl.},
  address   = {Cologne},
  issn      = {1866-0452},
  doi       = {10.3238/arztebl.2011.0359},
  pages     = {359 -- U30},
  year      = {2011},
  abstract  = {Background: The elderly need strength training more and more as they grow older to stay mobile for their everyday activities. The goal of training is to reduce the loss of muscle mass and the resulting loss of motor function. The dose-response relationship of training intensity to training effect has not yet been fully elucidated. Methods: PubMed was selectively searched for articles that appeared in the past 5 years about the effects and dose-response relationship of strength training in the elderly. Results: Strength training in the elderly (> 60 years) increases muscle strength by increasing muscle mass, and by improving the recruitment of motor units, and increasing their firing rate. Muscle mass can be increased through training at an intensity corresponding to 60\% to 85\% of the individual maximum voluntary strength. Improving the rate of force development requires training at a higher intensity (above 85\%), in the elderly just as in younger persons. It is now recommended that healthy old people should train 3 or 4 times weekly for the best results; persons with poor performance at the outset can achieve improvement even with less frequent training. Side effects are rare. Conclusion: Progressive strength training in the elderly is efficient, even with higher intensities, to reduce sarcopenia, and to retain motor function.},
  language  = {en}
}
@article{CarlsohnScharhagRosenbergerCasseletal.2011,
  author    = {Carlsohn, Anja and Scharhag-Rosenberger, Friederike and Cassel, Michael and Weber, Josefine and Guzman, Annette de Guzman and Mayer, Frank},
  title     = {Physical activity levels to estimate the energy requirement of adolescent athletes},
  series = {Pediatric exercise science},
  volume    = {23},
  journal   = {Pediatric exercise science},
  number    = {2},
  publisher = {Human Kinetics Publ.},
  address   = {Champaign},
  issn      = {0899-8493},
  pages     = {261 -- 269},
  year      = {2011},
  abstract  = {Adequate energy intake in adolescent athletes is considered important. Total energy expenditure (TEE) can be calculated from resting energy expenditure (REE) and physical activity level (PAL). However, validated PAL recommendations are available for adult athletes only. Purpose was to comprise physical activity data in adolescent athletes and to establish PAL recommendations for this population. In 64 competitive athletes (15.3 +/- 1.5yr, 20.5 +/- 2.0kg/m(2)) and 14 controls (15.1 +/- 1.1yr, 21 +/- 2.1kg/m(2)) TEE was calculated using 7-day activity protocols validated against doubly-labeled water. REE was estimated by Schofield-HW equation, and PAL was calculated as TEE:REE. Observed PAL in adolescent athletes (1.90 +/- 0.35) did not differ compared with controls (1.84 +/- 0.32, p = .582) and was lower than recommended for adult athletes by the WHO. In conclusion, applicability of PAL values recommended for adult athletes to estimate energy requirements in adolescent athletes must be questioned. Instead, a PAL range of 1.75-2.05 is suggested.},
  language  = {en}
}
@article{CarlsohnScharhagRosenbergerCasseletal.2011,
  author    = {Carlsohn, Anja and Scharhag-Rosenberger, Friederike and Cassel, Michael and Mayer, Frank},
  title     = {Resting metabolic rate in elite rowers and canoeists difference between indirect calorimetry and prediction},
  series = {Annals of nutrition \& metabolism : journal of nutrition, metabolic diseases and dietetics ; an official journal of International Union of Nutritional Sciences (IUNS)},
  volume    = {58},
  journal   = {Annals of nutrition \& metabolism : journal of nutrition, metabolic diseases and dietetics ; an official journal of International Union of Nutritional Sciences (IUNS)},
  number    = {3},
  publisher = {Karger},
  address   = {Basel},
  issn      = {0250-6807},
  doi       = {10.1159/000330119},
  pages     = {239 -- 244},
  year      = {2011},
  abstract  = {Background: Athletes may differ in their resting metabolic rate (RMR) from the general population. However, to estimate the RMR in athletes, prediction equations that have not been validated in athletes are often used. The purpose of this study was therefore to verify the applicability of commonly used RMR predictions for use in athletes. Methods: The RMR was measured by indirect calorimetry in 17 highly trained rowers and canoeists of the German national teams (BMI 24 +/- 2 kg/m(2), fat-free mass 69 +/- 15 kg). In addition, the RMR was predicted using Cunningham (CUN) and Harris-Benedict (HB) equations. A two-way repeated measures ANOVA was calculated to test for differences between predicted and measured RMR (alpha = 0.05). The root mean square percentage error (RMSPE) was calculated and the Bland-Altman procedure was used to quantify the bias for each prediction. Results: Prediction equations significantly underestimated the RMR in males (p < 0.001). The RMSPE was calculated to be 18.4\% (CUN) and 20.9\% (HB) in the entire group. The bias was 133 kcal/24 h for CUN and 202 kcal/24 h for HB. Conclusions: Predictions significantly underestimate the RMR in male heavyweight endurance athletes but not in females. In athletes with a high fat-free mass, prediction equations might therefore not be applicable to estimate energy requirements. Instead, measurement of the resting energy expenditure or specific prediction equations might be needed for the individual heavyweight athlete.},
  language  = {en}
}
@article{ScharhagRosenbergerWochatzOttoetal.2014,
  author    = {Scharhag-Rosenberger, Friederike and Wochatz, Monique and Otto, Christoph and Cassel, Michael and Mayer, Frank and Scharhag, J{\"u}rgen},
  title     = {Blood lactate concentrations are mildly affected by mobile gas exchange measurements},
  series = {International journal of sports medicine},
  volume    = {35},
  journal   = {International journal of sports medicine},
  number    = {7},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/s-0033-1354386},
  pages     = {590 -- 594},
  year      = {2014},
  abstract  = {We sought to investigate the effects of wearing a mobile respiratory gas analysis system during a treadmill test on blood lactate (bLa) concentrations and commonly applied bLa thresholds. A total of 16 recreational athletes (31 +/- 3 years, V0205: 58 6 ml min(-1)-kg(-1)) performed one multistage treadmill test with and one without gas exchange measurements (GEM and noGEM). The whole bLa curve, the lactate threshold (LT), the individual anaerobic thresholds according to Stegmann(IAT(sr)) and Dickhuth (IAT(Di)), and a fixed bLa concentration of 4 mmob.l(-1) (OBLA) were evaluated. The bLa curve was shifted slightly leftward in GEM compared to noGEM (P<0.05), whereas the heart rate response was not different between conditions (P= 0.89). There was no difference between GEM and noGEM for LT (2.61 +/- 0.34 vs. 2.64 +/- 0.39 m(-1) s(-1) P=0.49) and IAT(st) (3.47 +/- 0.42 vs. 3.55 +/- 0.47m-s(-1), P=0.12). However, IATD(Di) (3.57 +/- 0.39 vs. 3.66 +/- 0.44m-s(-1), P<0.01) and OBLA (3.85 +/- 0.46 vs. 3.96 +/- 0.47m-s-1, P<0.01) occurred at slower running velocities in GEM. The bLa response to treadmill tests is mildly affected by wearing a mobile gas analysis system. This also applies to bLa thresholds located at higher exercise intensities. While the magnitude of the effects is of little importance for recreational athletes, it might be relevant for elite athletes and scientific studies.},
  language  = {en}
}
@article{KochCasselLinneetal.2014,
  author    = {Koch, Sarah and Cassel, Michael and Linne, Karsten and Mayer, Frank and Scharhag, J{\"u}rgen},
  title     = {ECG and echocardiographic findings in 10-15-year-old elite athletes},
  series = {European journal of preventive cardiology : the official ESC journal for primary \& secondary cardiovascular prevention, rehabilitation and sports cardiology},
  volume    = {21},
  journal   = {European journal of preventive cardiology : the official ESC journal for primary \& secondary cardiovascular prevention, rehabilitation and sports cardiology},
  number    = {6},
  publisher = {Sage Publ.},
  address   = {London},
  issn      = {2047-4873},
  doi       = {10.1177/2047487312462147},
  pages     = {774 -- 781},
  year      = {2014},
  abstract  = {Background: Data on electrocardiographic and echocardiographic pre-participation screening findings in paediatric athletes are limited.},
  language  = {en}
}
@inproceedings{HainCasselIntziegiannietal.2014,
  author    = {Hain, Gerrit and Cassel, Michael and Intziegianni, Konstantina and Mayer, Frank},
  title     = {Achilles tendon cross-sectional area changes during maximal voluntary isometric plantar-flexion contraction in healthy individuals.},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {46},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {47 -- 47},
  year      = {2014},
  language  = {en}
}
@inproceedings{IntziegianniCasselHainetal.2014,
  author    = {Intziegianni, Konstantina and Cassel, Michael and Hain, Gerrit and Fr{\"o}hlic, Katja and Mayer, Frank},
  title     = {Reliability of sonographic assessment of Achilles tendon cross-sectional area at rest and maximal voluntary contraction},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {46},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {47 -- 47},
  year      = {2014},
  language  = {en}
}
@inproceedings{RischCasselMesserschmidtetal.2014,
  author    = {Risch, Lucie and Cassel, Michael and Messerschmidt, Janin and Intziegianni, Konstantina and Mayer, Frank},
  title     = {Consistency and reliability of examining intratendinous blood flow in Achilles tendinopathy patients using doppler ultrasonography},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {46},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {46 -- 46},
  year      = {2014},
  language  = {en}
}
@inproceedings{ReschkeCasselIntziegiannietal.2014,
  author    = {Reschke, Antje and Cassel, Michael and Intziegianni, Konstantina and Mayer, Frank},
  title     = {Intra- and inter-rater reliability of sonographic cross-sectional area measurements in asymptomatic patella tendons},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {46},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {927 -- 928},
  year      = {2014},
  language  = {en}
}
@inproceedings{EngelKopinskiCarlsohnetal.2014,
  author    = {Engel, Tilman and Kopinski, Stephan and Carlsohn, Anja and Cassel, Michael and Mayer, Frank},
  title     = {Correlation of sonographic subcutaneous adipose tissue measurements with air displacement plethysmography and calipermetry},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {46},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {539 -- 539},
  year      = {2014},
  language  = {en}
}
@article{CasselMuellerMoseretal.2019,
  author    = {Cassel, Michael and M{\"u}ller, Juliane and Moser, Othmar and Strempler, Mares Elaine and Reso, Judith and Mayer, Frank},
  title     = {Orthopedic Injury Profiles in Adolescent Elite Athletes},
  series = {Frontiers in Physiology},
  volume    = {10},
  journal   = {Frontiers in Physiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2019.00544},
  pages     = {10},
  year      = {2019},
  abstract  = {Aim: The aim of the study was to identify common orthopedic sports injury profiles in adolescent elite athletes with respect to age, sex, and anthropometrics. Methods: A retrospective data analysis of 718 orthopedic presentations among 381 adolescent elite athletes from 16 different sports to a sports medical department was performed. Recorded data of history and clinical examination included area, cause and structure of acute and overuse injuries. Injury-events were analyzed in the whole cohort and stratified by age (11-14/15-17 years) and sex. Group differences were tested by chi-squared-tests. Logistic regression analysis was applied examining the influence of factors age, sex, and body mass index (BMI) on the outcome variables area and structure (a = 0.05). Results: Higher proportions of injury-events were reported for females (60\%) and athletes of the older age group (66\%) than males and younger athletes. The most frequently injured area was the lower extremity (47\%) followed by the spine (30.5\%) and the upper extremity (12.5\%). Acute injuries were mainly located at the lower extremity (74.5\%), while overuse injuries were predominantly observed at the lower extremity (41\%) as well as the spine (36.5\%). Joints (34\%), muscles (22\%), and tendons (21.5\%) were found to be the most often affected structures. The injured structures were different between the age groups (p = 0.022), with the older age group presenting three times more frequent with ligament pathology events (5.5\%/2\%) and less frequent with bony problems (11\%/20.5\%) than athletes of the younger age group. The injured area differed between the sexes (p = 0.005), with males having fewer spine injury-events (25.5\%/34\%) but more upper extremity injuries (18\%/9\%) than females. Regression analysis showed statistically significant influence for BMI (p = 0.002) and age (p = 0.015) on structure, whereas the area was significantly influenced by sex (p = 0.005). Conclusion: Events of soft-tissue overuse injuries are the most common reasons resulting in orthopedic presentations of adolescent elite athletes. Mostly, the lower extremity and the spine are affected, while sex and age characteristics on affected area and structure must be considered. Therefore, prevention strategies addressing the injury-event profiles should already be implemented in early adolescence taking age, sex as well as injury entity into account.},
  language  = {en}
}
@article{CasselRischIntziegiannietal.2018,
  author    = {Cassel, Michael and Risch, Lucie and Intziegianni, Konstantina and Mueller, Juliane and Stoll, Josefine and Brecht, Pia and Mayer, Frank},
  title     = {Incidence of achilles and patellar tendinopathy in adolescent elite athletes},
  series = {International journal of sports medicine},
  volume    = {39},
  journal   = {International journal of sports medicine},
  number    = {9},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/a-0633-9098},
  pages     = {726 -- 732},
  year      = {2018},
  abstract  = {The study investigated the incidence of Achilles and patellar tendinopathy in adolescent elite athletes and non-athletic controls. Furthermore, predictive and associated factors for tendinopathy development were analyzed. The prospective study consisted of two measurement days (M1/M2) with an interval of 3.2 +/- 0.9 years. 157 athletes (12.1 +/- 0.7 years) and 25 controls (13.3 +/- 0.6 years) without Achilles/patellar tendinopathy were included at Ml. Clinical and ultrasound examinations of both Achilles (AT) and patellar tendons (PT) were performed. Main outcome measures were incidence tendinopathy and structural intratendinous alterations (hypo-/hyperechogenicity, vascularization) at M2 [\%]. Incidence of Achilles tendinopathy was 1\% in athletes and 0\% in controls. Patellar tendinopathy was more frequent in athletes (13 \%)than in controls (4\%). Incidence of intratendinous alterations in ATs was 1-2\% in athletes and 0 \% in controls, whereas in PTs it was 4-6 \% in both groups (p >0.05). Intratendinous alterations at M2 were associated with patellar tendinopathy in athletes (p <= 0.01). Intratendinous alterations at M1, anthropometric data, training amount, sports or sex did not predict tendinopathy development (p>0.05). Incidence often dinopathy and intratendinous alterations in adolescent athletes is low in ATs and more common in PTs. Development of intratendinous alterations in PT is associated with tend in opathy. However, predictive factors could not be identified.},
  language  = {en}
}
@article{BaurMuellerHirschmuelleretal.2011,
  author    = {Baur, Heiner and M{\"u}ller, Steffen and Hirschm{\"u}ller, Anja and Cassel, Michael and Weber, Josefine and Mayer, Frank},
  title     = {Comparison in lower leg neuromuscular activity between runners with unilateral mid-portion Achilles tendinopathy and healthy individuals},
  series = {Journal of electromyography and kinesiology},
  volume    = {21},
  journal   = {Journal of electromyography and kinesiology},
  number    = {3},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {1050-6411},
  doi       = {10.1016/j.jelekin.2010.11.010},
  pages     = {499 -- 505},
  year      = {2011},
  abstract  = {Neuromuscular control in functional situations and possible impairments due to Achilles tendinopathy are not well understood. Thirty controls (CO) and 30 runners with Achilles tendinopathy (AT) were tested on a treadmill at 3.33 m s(-1) (12 km h(-1)). Neuromuscular activity of the lower leg (tibialis anterior, peroneal, and gastrocnemius muscle) was measured by surface electromyography. Mean amplitude values (MAV) for the gait cycle phases preactivation, weight acceptance and push-off were calculated and normalised to the mean activity of the entire gait cycle. MAVs of the tibialis anterior did not differ between CO and AT in any gait cycle phase. The activation of the peroneal muscle was lower in AT in weight acceptance (p = 0.006), whereas no difference between CO and AT was found in preactivation (p = 0.71) and push-off (p = 0.83). Also, MAVs of the gastrocnemius muscle did not differ between AT and CO in preactivity (p = 0.71) but were reduced in AT during weight acceptance (p = 0.001) and push-off (p = 0.04). Achilles tendinopathy does not seem to alter pre-programmed neural control but might induce mechanical deficits of the lower extremity during weight bearing (joint stability). This should be addressed in the therapy process of AT.},
  language  = {en}
}
@article{WahmkowCasselMayeretal.2017,
  author    = {Wahmkow, Gunnar and Cassel, Michael and Mayer, Frank and Baur, Heiner},
  title     = {Effects of different medial arch support heights on rearfoot kinematics},
  series = {PLoS one},
  volume    = {12},
  journal   = {PLoS one},
  number    = {3},
  publisher = {PLoS},
  address   = {Lawrence, Kan.},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0172334},
  year      = {2017},
  abstract  = {Background Foot orthoses are usually assumed to be effective by optimizing mechanically dynamic rearfoot configuration. However, the effect from a foot orthosis on kinematics that has been demonstrated scientifically has only been marginal. The aim of this study was to examine the effect of different heights in medial arch-supported foot orthoses on rear foot motion during gait. Methods Nineteen asymptomatic runners (36±11years, 180±5cm, 79±10kg; 41±22km/week) participated in the study. Trials were recorded at 3.1 mph (5 km/h) on a treadmill. Athletes walked barefoot and with 4 different not customized medial arch-supported foot orthoses of various arch heights (N:0 mm, M:30 mm, H:35 mm, E:40mm). Six infrared cameras and the `Oxford Foot Model´ were used to capture motion. The average stride in each condition was calculated from 50 gait cycles per condition. Eversion excursion and internal tibia rotation were analyzed. Descriptive statistics included calculating the mean ± SD and 95\% CIs. Group differences by condition were analyzed by one factor (foot orthoses) repeated measures ANOVA (α = 0.05). Results Eversion excursion revealed the lowest values for N and highest for H (B:4.6°±2.2°; 95\% CI [3.1;6.2]/N:4.0°±1.7°; [2.9;5.2]/M:5.2°±2.6°; [3.6;6.8]/H:6.2°±3.3°; [4.0;8.5]/E:5.1°±3.5°; [2.8;7.5]) (p>0.05). Range of internal tibia rotation was lowest with orthosis H and highest with E (B:13.3°±3.2°; 95\% CI [11.0;15.6]/N:14.5°±7.2°; [9.2;19.6]/M:13.8°±5.0°; [10.8;16.8]/H:12.3°±4.3°; [9.0;15.6]/E:14.9°±5.0°; [11.5;18.3]) (p>0.05). Differences between conditions were small and the intrasubject variation high. Conclusion Our results indicate that different arch support heights have no systematic effect on eversion excursion or the range of internal tibia rotation and therefore might not exert a crucial influence on rear foot alignment during gait.},
  language  = {en}
}
@article{CasselBaurHirschmuelleretal.2015,
  author    = {Cassel, Michael and Baur, Heiner and Hirschmueller, Anja and Carlsohn, Anja and Fr{\"o}hlich, Katja and Mayer, Frank},
  title     = {Prevalence of Achilles and patellar tendinopathy and their association to intratendinous changes in adolescent athletes},
  series = {Scandinavian journal of medicine \& science in sports},
  volume    = {25},
  journal   = {Scandinavian journal of medicine \& science in sports},
  number    = {3},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0905-7188},
  doi       = {10.1111/sms.12318},
  pages     = {e310 -- e318},
  year      = {2015},
  abstract  = {Achilles (AT) and patellar tendons (PT) are commonly affected by tendinopathy in adult athletes but prevalence of symptoms and morphological changes in adolescents is unclear. The study aimed to determine prevalence of tendinopathy and intratendinous changes in ATs and PTs of adolescent athletes. A total of 760 adolescent athletes (13.0 +/- 1.9 years; 160 +/- 13cm; 50 +/- 14kg) were examined. History, local clinical examination, and longitudinal Doppler ultrasound analysis for both ATs and PTs were performed including identification of intratendinous echoic changes and vascularization. Diagnosis of tendinopathy was complied clinically in case of positive history of tendon pain and tendon pain on palpation. Achilles tendinopathy was diagnosed in 1.8\% and patellar tendinopathy in 5.8\%. Vascularizations were visible in 3.0\% of ATs and 11.4\% of PTs, hypoechogenicities in 0.7\% and 3.2\% as well as hyperechogenicities in 0\% and 0.3\%, respectively. Vascularizations and hypoechogenicities were statistically significantly more often in males than in females (P0.02). Subjects with patellar tendinopathy had higher prevalence of structural intratendinous changes than those without PT symptoms (P0.001). In adolescent athletes, patellar tendinopathy is three times more frequent compared with Achilles tendinopathy. Longitudinal studies are necessary to investigate physiological or pathological origin of vascularizations and its predictive value in development of tendinopathy.},
  language  = {en}
}