TY - JOUR A1 - Baur, Heiner A1 - Hirschmüller, Anja A1 - Cassel, Michael A1 - Müller, Steffen A1 - Mayer, Frank T1 - Gender-specific neuromuscular activity of the M. peroneus longus in healthy runners : a descriptive laboratory study N2 - 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. Y1 - 2010 UR - http://www.sciencedirect.com/science/journal/02680033 U6 - https://doi.org/10.1016/j.clinbiomech.2010.06.009 SN - 0268-0033 ER - TY - JOUR A1 - Baur, Heiner A1 - Müller, Steffen A1 - Hirschmüller, Anja A1 - Cassel, Michael A1 - Weber, Josefine A1 - Mayer, Frank T1 - Comparison in lower leg neuromuscular activity between runners with unilateral mid-portion Achilles tendinopathy and healthy individuals JF - Journal of electromyography and kinesiology N2 - 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. KW - Ankle joint KW - Electromyography KW - Overuse injury KW - Running gait Y1 - 2011 U6 - https://doi.org/10.1016/j.jelekin.2010.11.010 SN - 1050-6411 VL - 21 IS - 3 SP - 499 EP - 505 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Mayer, Frank A1 - Scharhag-Rosenberger, Friederike A1 - Carlsohn, Anja A1 - Cassel, Michael A1 - Müller, Steffen A1 - Scharhag, Jürgen T1 - The intensity and effects of strength training in the elderly JF - Deutsches Ärzteblatt international : a weekly online journal of clinical medicine and public health N2 - 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. Y1 - 2011 U6 - https://doi.org/10.3238/arztebl.2011.0359 SN - 1866-0452 VL - 108 IS - 21 SP - 359 EP - U30 PB - Dt. Ärzte-Verl. CY - Cologne ER - TY - JOUR A1 - Mayer, Frank A1 - Bonaventura, Klaus A1 - Cassel, Michael A1 - Müller, Steffen A1 - Weber, Josefine A1 - Scharhag-Rosenberger, Friederike A1 - Carlsohn, Anja A1 - Baur, Heiner A1 - Scharhag, Jürgen T1 - Medical results of preparticipation examination in adolescent athletes JF - British journal of sports medicine : the journal of sport and exercise medicine N2 - Background Preparticipation examinations (PPE) are frequently used to evaluate eligibility for competitive sports in adolescent athletes. Nevertheless, the effectiveness of these examinations is under debate since costs are high and its validity is discussed controversial. Purpose To analyse medical findings and consequences in adolescent athletes prior to admission to a sports school. Methods In 733 adolescent athletes (318 girls, 415 boys, age 12.3+/-0.4, 16 sports disciplines), history and clinical examination (musculoskeletal, cardiovascular, general medicine) was performed to evaluate eligibility. PPE was completed by determination of blood parameters, ECG at rest and during ergometry, echocardiography and x-rays and ultrasonography if indicated. Eligibility was either approved or rated with restriction. Recommendations for therapy and/or prevention were given to the athletes and their parents. Results Historical (h) and clinical (c) findings (eg, pain, verified pathologies) were more frequent regarding the musculoskeletal system (h: 120, 16.4%; c: 247, 33.7%) compared to cardiovascular (h: 9, 1.2%; c: 23, 3.1%) or general medicine findings (h: 116, 15.8%; c: 71, 9.7%). ECG at rest was moderately abnormal in 46 (6.3%) and severely abnormal in 25 athletes (3.4%). Exercise ECG was suspicious in 25 athletes (3.4%). Relevant echocardiographic abnormalities were found in 17 athletes (2.3%). In 52 of 358 cases (14.5%), x-rays led to diagnosis (eg, Spondylolisthesis). Eligibility was temporarily restricted in 41 athletes (5.6%). Three athletes (0.4%) had to be excluded from competitive sports. Therapy (eg, physiotherapy, medication) and/or prevention (sensorimotor training, vaccination) recommendations were deduced due to musculoskeletal (t:n = 76,10.3%; p:n = 71,9.8%) and general medicine findings (t:n = 80, 10.9%; p:n = 104, 14.1%). Conclusion Eligibility for competitive sports is restricted in only 5.5% of adolescent athletes at age 12. Eligibility refusals are rare. However, recommendations for therapy and prevention are frequent, mainly regarding the musculoskeletal system. In spite of time and cost consumption, adolescent preparticipation before entering a career in high-performance sports is supported. Y1 - 2012 U6 - https://doi.org/10.1136/bjsports-2011-090966 SN - 0306-3674 VL - 46 IS - 7 SP - 524 EP - 530 PB - BMJ Publ. Group CY - London 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 - Baur, Heiner A1 - Hirschmüller, Anja A1 - Müller, Steffen A1 - Cassel, Michael A1 - Mayer, Frank T1 - Is EMG of the lower leg dependent on weekly running mileage? JF - International journal of sports medicine N2 - Neuromuscular activity of the lower leg is dependent on the task performed, speed of movement and gender. Whether training volume influences neuromuscular activity is not known. The EMG of physically active persons differing in running mileage was analysed to investigate this. 55 volunteers were allocated to a low (LM: < 30 km), intermediate (IM: > 30 km & < 45 km) or high mileage (HM: > 45 km) group according to their weekly running volume. Neuromuscular activity of the lower leg was measured during running (3.33 m.s(-1)). Mean amplitude values for preactivation, weight acceptance and push-off were calculated and normalised to the mean activity of the entire gait cycle. Higher activity in the gastrocnemius group was observed in weight acceptance in LM compared to IM (+30%) and HM (+25%) but lower activity was present in the push-off for LM compared to IM and HM. For the peroneal muscle, differences were present in the push-off where HM showed increased activity compared to IM (+24%) and LM (+60%). The tibial muscle revealed slightly lower activity during preactivation for the high mileage runners. Neuromuscular activity differs during stance between the high and intermediate group compared to low mileage runners. Slight adaptations in neuromuscular activation indicate a more target-oriented activation strategy possibly due to repetitive training in runners with higher weekly mileage. KW - locomotion KW - neuromuscular control KW - running gait KW - training volume Y1 - 2012 U6 - https://doi.org/10.1055/s-0031-1286250 SN - 0172-4622 VL - 33 IS - 1 SP - 53 EP - 57 PB - Thieme CY - Stuttgart ER - TY - CHAP A1 - Intziegianni, Konstantina A1 - Cassel, Michael A1 - Müller, Steffen A1 - Mayer, Frank T1 - Ultrasound evaluation of the patellar tendon cross-sectional area and its relation to maximum force T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2012 SN - 0195-9131 VL - 44 SP - 714 EP - 714 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - CHAP A1 - Müller, Steffen A1 - Cassel, Michael A1 - Müller, Juliane A1 - Stoll, Josefine A1 - Baur, Heiner A1 - Mayer, Frank T1 - Trunk strength in adolescent athletes with Spondylolisthesis with/without back pain during training: Pilot study T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2014 SN - 0195-9131 SN - 1530-0315 VL - 46 IS - 5 SP - 642 EP - 642 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - 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 - Müller, Steffen A1 - Müller, Juliane A1 - Stoll, Josefine A1 - Prieske, Olaf A1 - Cassel, Michael A1 - Mayer, Frank T1 - Incidence of back pain in adolescent athletes BT - a prospective study JF - BMC sports science, medicine & rehabilitation N2 - 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. KW - Pain occurrence KW - Young athletes KW - Injury KW - Training volume Y1 - 2016 U6 - https://doi.org/10.1186/s13102-016-0064-7 SN - 2052-1847 VL - 8 PB - BioMed Central CY - London ER -