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 - Wahmkow, Gunnar A1 - Cassel, Michael A1 - Mayer, Frank A1 - Baur, Heiner T1 - Effects of different medial arch support heights on rearfoot kinematics JF - PLoS one N2 - 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. Y1 - 2017 U6 - https://doi.org/10.1371/journal.pone.0172334 SN - 1932-6203 VL - 12 IS - 3 PB - PLoS CY - Lawrence, Kan. ER - TY - JOUR A1 - Cassel, Michael A1 - Baur, Heiner A1 - Hirschmueller, Anja A1 - Carlsohn, Anja A1 - Fröhlich, Katja A1 - Mayer, Frank T1 - Prevalence of Achilles and patellar tendinopathy and their association to intratendinous changes in adolescent athletes JF - Scandinavian journal of medicine & science in sports N2 - 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. KW - Prevalence KW - tendinopathy KW - sonography KW - Doppler ultrasound KW - vascularization KW - hypoechogenicities KW - hyperechogenicities KW - adolescent athletes Y1 - 2015 U6 - https://doi.org/10.1111/sms.12318 SN - 0905-7188 SN - 1600-0838 VL - 25 IS - 3 SP - e310 EP - e318 PB - Wiley-Blackwell CY - Hoboken 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 - GEN A1 - Wahmkow, Gunnar A1 - Cassel, Michael A1 - Mayer, Frank A1 - Baur, Heiner T1 - Effects of different medial arch support heights on rearfoot kinematics N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 348 Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-402934 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 - 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 -