TY - JOUR A1 - Intziegianni, Konstantina A1 - Cassel, Michael A1 - König, Niklas A1 - Müller, Steffen A1 - Fröhlich, Katja A1 - Mayer, Frank T1 - Ultrasonography for the assessment of the structural properties of the Achilles tendon in asymptomatic individuals: An intra-rater reproducibility study JF - Isokinetics and exercise science : official journal of the European Isokinetic Society N2 - BACKGROUND: Reproducible measurements of tendon structural properties are a prerequisite for accurate diagnosis of tendon disorders and for determination of their mechanical properties. Despite the widely used application of Ultrasonography (US) in musculoskeletal assessment, its operator dependency and lack of standardization influences the consistency of the measurement. OBJECTIVE: To evaluate the intra-rater reproducibility of a standardized US method assessing the structural properties of the Achilles tendon (AT). METHODS: Sixteen asymptomatic participants were positioned prone on an isokinetic dynamometer with the knee extended and ankle at 90. flexion. US was used to assess AT-length, cross-sectional area (CSA), and AT-elongation during isometric plantarflexion contraction. The intra-rater reproducibility was assessed by ICC (2.1), Test-Retest Variability (TRV, %), Bland-Altman analyses (Bias +/- LoA [1.96*SD]), and Standard-Error of Measurement (SEM). RESULTS: Measurements of AT-length demonstrated an ICC of 0.93, TRV of 4.5 +/- 3.9%, Bias +/- LoA of -2.8 +/- 25.0 mm and SEM of 6.6 mm. AT-CSA showed an ICC of 0.79, TRV of 8.7 +/- 9.6%, Bias +/- LoA of 1.7 +/- 19.4 mm(2) and SEM of 5.3 mm(2). AT-elongation revealed an ICC of 0.92, TRV of 12.9 +/- 8.9%, Bias +/- LoA of 0.3 +/- 5.7 mm and SEM of 1.5 mm. CONCLUSIONS: The presented methodology allows a reproducible assessment of Achilles tendon structural properties when performed by a single rater. KW - Ultrasonography KW - Achilles tendon KW - reproducibility KW - isokinetic Y1 - 2015 U6 - https://doi.org/10.3233/IES-150586 SN - 0959-3020 SN - 1878-5913 VL - 23 IS - 4 SP - 263 EP - 270 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Kopinski, Stephan A1 - Engel, Tilman A1 - Cassel, Michael A1 - Fröhlich, Katja A1 - Mayer, Frank A1 - Carlsohn, Anja T1 - Ultrasound Applied to Subcutaneous Fat Tissue Measurements in International Elite Canoeists JF - International journal of sports medicine N2 - Subcutaneous adipose tissue (SAT) measurements with ultrasound have recently been introduced to assess body fat in elite athletes. However, appropriate protocols and data on various groups of athletes are missing. We investigated intra-rater reliability of SAT measurements using ultrasound in elite canoe athletes. 25 international level canoeists (18 male, 7 female; 23 +/- 4 years; 81 +/- 11 kg; 1.83 +/- 0.09 m; 20 +/- 3 training h/wk) were measured on 2 consecutive days. SAT was assessed with B-mode ultrasound at 8 sites (ISAK): triceps, subscapular, biceps, iliac crest, supraspinal, abdominal, front thigh, medial calf, and quantified using image analysis software. Data was analyzed descriptively (mean +/- SD, [range]). Coefficient of variation (CV %), intraclass correlation coefficient (ICC, 2.1) and absolute (LoA) and ratio limits of agreement (RLoA) were calculated for day-to-day reliability. Mean sum of SAT thickness was 30.0 +/- 19.4 mm [8.0, 80.1 mm], with 3.9 +/- 1.8 mm [1.2 mm subscapular, 8.0 mm abdominal] for individual sites. CV for the sum of sites was 4.7 %, ICC 0.99, LoA 1.7 +/- 3.6 mm, RLoA 0.940 (*/divided by 1.155). Measuring SAT with ultrasound has proved to have excellent day-to-day reliability in elite canoe athletes. Recommendations for standardization of the method will further increase accuracy and reproducibility. KW - subcutaneous adipose tissue KW - skinfold thickness KW - elite athletes KW - body composition KW - ultrasonography Y1 - 2015 U6 - https://doi.org/10.1055/s-0035-1555857 SN - 0172-4622 SN - 1439-3964 VL - 36 IS - 14 SP - 1134 EP - 1141 PB - Thieme CY - Stuttgart ER - TY - JOUR A1 - Cassel, Michael A1 - Stoll, Josefine A1 - Mayer, Frank T1 - Tendinopathies of the Lower Extremities in Sport - Diagnostics and Therapy JF - Sportverletzung, Sportschaden : Grundlagen, Prävention, Rehabilitation N2 - Tendinopathies are frequently the cause of chronic, load-dependent complaints of the lower extremity. Commonly, the large tendons of the ankle and knee joints are affected, especially the Achilles and patellar tendons. Repeated overuse in sports and/or daily activities is assumed as the aetiology. Besides the clinical examination including a comprehensive anamnesis of pain and training/loading, sonographic imaging has a high training/loading relevance for the diagnosis of tendon pathologies of the lower extremity. Training concepts are considered in first line as the treatment of choice. A combination with physical therapy interventions can be useful. In cases of a more severe pathology and long-standing complaints multimodal therapeutic options should be employed. The use of surgical treatment procedures should only be taken into account in case of failed response to conservative treatment. KW - Tendinopathy KW - sonography KW - principles of therapy Y1 - 2015 U6 - https://doi.org/10.1055/s-0034-1399668 SN - 0932-0555 SN - 1439-1236 VL - 29 IS - 2 SP - 87 EP - 98 PB - Thieme CY - Stuttgart ER - TY - CHAP A1 - Risch, Lucie A1 - Bashford, Greg A1 - Kulig, Kornelia A1 - Kaplick, Hannes A1 - Mayer, Frank A1 - Cassel, Michael T1 - Spatial frequency analysis identifies altered local Micromorphology in adolescent athletes with Achilles tendinopathy T2 - Medicine and science in sports and exercise : MSSE ; official journal of the American College of Sports Medicine Y1 - 2020 U6 - https://doi.org/10.1249/01.mss.0000670932.99564.57 SN - 0195-9131 SN - 1530-0315 VL - 52 SP - 82 EP - 82 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Cassel, Michael A1 - Stoll, Josefine A1 - Schugardt, Monique A1 - Mayer, Frank T1 - Overuse and injury prevention JF - Elite youth cycling Y1 - 2019 SN - 978-1-315-11077-6 SN - 978-1-138-08684-5 SP - 141 EP - 159 PB - Routledge CY - London ER - TY - JOUR A1 - Risch, Lucie A1 - Stoll, Josefine A1 - Schomöller, Anne A1 - Engel, Tilman A1 - Mayer, Frank A1 - Cassel, Michael T1 - Intraindividual Doppler Flow Response to Exercise Differs Between Symptomatic and Asymptomatic Achilles Tendons JF - Frontiers in physiology N2 - 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.” KW - achilles tendinopathy KW - tendinosis KW - neovascularization KW - ultrasound KW - advanced dynamic flow KW - sonography Y1 - 2021 U6 - https://doi.org/10.3389/fphys.2021.617497 SN - 1664-042X VL - 12 SP - 1 EP - 8 PB - Frontiers Research Foundation CY - Lausanne, Schweiz ER - TY - JOUR A1 - Cassel, Michael A1 - Müller, Steffen A1 - Carlsohn, Anja A1 - Baur, Heiner A1 - Jerusel, N. A1 - Mayer, Frank T1 - Intra- and interrater variability of sonographic investigations of patella and achilles tendons JF - Sportverletzung, Sportschaden : Grundlagen, Prävention, Rehabilitation N2 - Background: Clinical examinations of tendon disorders routinely include ultrasound examinations, despite the fact that availability of data concerning validity criteria of these measurements are limited. The present study therefore aims to evaluate the reliability of measurements of Achilles- and Patella tendon diameter and in the detection of structural adaptations. Materials and Methods: In 14 healthy, recreationally active subjects both asymptomatic Achilles (AT) and patella tendons (PT) were measured twice by two examiners in a test-retest design. Besides the detection of anteroposterior (a.p.-) and mediolateral (m.l.-) diameters, areas of hypoechogenicity and neovascularisation were registered. Data were analysed descriptively with calculation of test-retest variability (TRV), intraclass-correlation coefficient (ICC) and Bland and Altman's plots with bias and 95% limits of agreement (LOA). Results: Intra- and interrater differences of AT- and PT-a.p.-diameter varied from 0.2 - 1.2 mm, those of AT- and PT-m.l-diameter from 0.7-5.1 mm. Areas of hypoechogenicity were visible in 24% of the tendons, while 15% showed neovascularisations. Intrarater AT-a.p.-diameters showed sparse deviations (TRV 4.5-7.4%; ICC 0.60-0.84; bias -0.05-0.07 mm; LOA-0.6-0.5 to -1.1 - 1.0 mm), while interrater AT- and PT-m.l.-diameters were highly variable (TRV 13.7-19.7%; ICC 0.11-0.20; bias -1.4-4.3 mm; LOA-5.5-2.7 to -10.5 - 1.9 mm). Conclusion: Our results suggest that the measurement of AT- and PT-a.p.-diameters is a reliable parameter. In contrast, reproducibility of AT- and PT-m.l.-diameters is questionable. The study corroborates the presence of hypoechogenicity and neovascularisation in asymptomatic tendons. KW - ultrasound KW - Achilles tendon KW - Patella tendon KW - intra- and inter-rater variability KW - tendon diameter Y1 - 2012 U6 - https://doi.org/10.1055/s-0031-1281839 SN - 0932-0555 VL - 26 IS - 1 SP - 21 EP - 26 PB - Thieme CY - Stuttgart ER - TY - JOUR A1 - Risch, Lucie A1 - Mayer, Frank A1 - Cassel, Michael T1 - Doppler flow response following running exercise differs between healthy and tendinopathic Achilles tendons JF - Frontiers in Physiology N2 - 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. KW - neovascularization KW - tendinopathy KW - Doppler ultrasound KW - Advanced Dynamic Flow KW - athlete KW - sonography Y1 - 2021 U6 - https://doi.org/10.3389/fphys.2021.650507 SN - 1664-042X VL - 12 PB - Frontiers Research Foundation CY - Lausanne ER - TY - GEN A1 - Joost, Theresa Anna A1 - Brecht, Pia A1 - Mayer, Frank A1 - Cassel, Michael T1 - Feasibility of open low-field MRI measurements in adolescent athletes with spondylolisthesis T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine N2 - PURPOSE: To determine the feasibility of upright compared to supine MRI measurements to determine characteristics of the lumbar spine in AA with spondylolisthesis. METHODS: Ten AA (n=10; m/f: 4/6; 14.5±1.7y; 163±7cm; 52±8kg) from various sports, diagnosed with spondylolisthesis grade I-II Meyerding confirmed by x-ray in standing lateral view, were included. Open low-field MRI images (0.25 Tesla) in upright (82°) and supine (0°) position were evaluated by two observers. Medical imaging software was used to measure the anterior translation (AT, mm), lumbosacral joint angle (LSJA, °) and lordosis angle (LA, °). Reliability was analyzed by the intra-rater correlation coefficient (ICC) and standard error of measurements (SEM). RESULTS: Due to motion artifacts during upright position, measures of three participants had to be excluded. Between observers, AT ranged from 4.2±2.7mm to 5.5±1.9mm (ICC=0.94, SEM=0.6mm) in upright and from 4.9±2.4mm to 5.9±3.0mm (ICC=0.89, SEM=0.9mm) in supine position. LSJA varied from 5.1±2.2° to 7.3±1.5° (ICC=0.54, SEM=1.5°) in upright and from 9.8±2.5° to 10±2.4° (ICC=0.73, SEM=1.1°) in supine position. LA differed from 58.8±14.6° to 61.9±6° (ICC=0.94, SEM=1.19°) in upright and from 51.9±11.7° to 52.6±11.1° (ICC=0.98, SEM=1.59°) in supine position. CONCLUSIONS: Determination of AT and LA showed good to excellent reliability in both, upright and supine position. In contrast, reliability of LSJA had only moderate to good correlation between observers and should therefore be interpreted with caution. However, motion artifacts should be taken into consideration during upright imaging procedures. Y1 - 2020 U6 - https://doi.org/10.1249/01.mss.0000683832.74059.9d SN - 0195-9131 SN - 1530-0315 VL - 52 IS - 17 SP - 790 EP - 790 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Cassel, Michael A1 - Mayer, Frank T1 - Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain JF - Frontiers in physiology N2 - 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. KW - SEMG-pattern KW - back pain KW - pre-activity KW - drop jump KW - neuromuscular KW - trunk KW - performance KW - young athletes Y1 - 2017 U6 - https://doi.org/10.3389/fphys.2017.00274 SN - 1664-042X VL - 8 PB - Frontiers Research Foundation CY - Lausanne ER -