TY - JOUR A1 - Hirschmueller, Anja A1 - Frey, Virginie A1 - Deibert, Peter A1 - Konstantinidis, Lukas A1 - Mayer, Frank A1 - Suedkamp, Norbert A1 - Helwig, Peter T1 - Powerdopplersonografische Befunde der Achillessehnen von 953 Langstreckenlaeufern : eine Querschnittsstudie N2 - Aim: The aim of this cross-sectional study was to assess the frequency of tendinopathy-typical Doppler sonographic changes in the Achilles tendons of long distance runners and to correlate these findings with anamnestic and anthropometric data of the subjects. Materials and Methods: 1906 Achilles tendons of 953 long distance runners were examined by ultrasound and power Doppler (Toshiba Aplio SSA-770A/80 12 MHz). Ultrasound images (spindle-shaped thickening, hypoechoic/hyperechoic lesions, neovascularizations) were analyzed in relation to the runners' anthropometrical data and history of Achilles tendon complaints. Results: In asymptomatic runners as well as in the overall group, there was a statistically significant correlation between tendon thickness and age, height and weight (CC 0.24 - 0.38, p < 0.001). Runners with current or healed Achilles tendon complaints displayed a statistically significant thickening of the tendons, as well as an increase in hypoechoic lesions and neovascularizations (p < 0.001). While grayscale abnormalities were rarely found in asymptomatic runners (< 10%), neovascularization was detected in 35% of healthy test persons using the high-resolution power Doppler "Advanced Dynamic Flow". Conclusion: Contrary to frequent assumption, neovascularization is often found in tendons of asymptomatic runners, using modern power Doppler equipment. The pathological relevance of single microvessels in asymptomatic tendons must, therefore, be critically discussed. Y1 - 2010 UR - http://www.thieme-connect.com/ejournals/toc/ultraschall U6 - https://doi.org/10.1055/s-0029-1245189 SN - 0172-4614 ER - TY - JOUR A1 - Carlsohn, Anja A1 - Rohn, Sascha A1 - Mayer, Frank A1 - Schweigert, Florian J. T1 - Physical activity, antioxidant status, and protein modification in adolescent athletes N2 - Exercise may increase reactive oxygen species production, which might impair cell integrity and contractile function of muscle cells. However, little is known about the effect of regular exercise on the antioxidant status of adolescents. Purpose: This study aimed to evaluate the impact of exercise on the antioxidant status and protein modifications in adolescent athletes. Methods: In 90 athletes and 18 controls (16 +/- 2 yr), exercise-related energy expenditure was calculated on the basis of a 7-d activity protocol. Antioxidant intake and plasma concentrations of alpha-tocopherol, carotenoids, and uric acid were analyzed. Plasma antioxidant activity was determined by Trolox equivalent (TE) antioxidant capacity and electron spin resonance spectrometry. Protein modifications were assessed with structural changes of transthyretin using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Data were analyzed by two-way ANOVA and post hoc by the Tukey-Kramer test (alpha = 0.05). Results: Antioxidant intake correlated with energy intake and was within the recommended daily allowance for vitamins C and E and beta-carotene. Plasma levels of neither nutritional antioxidants nor uric acid differed between the groups. TE antioxidant capacity was higher in athletes (men = 1.47 perpendicular to 0.2 mmol TE per liter, women = 1.45 perpendicular to 0.2 mmol TE per liter) compared with controls (men = 1.17 +/- 0.04 mmol TE per liter, women = 1.14 +/- 0.04 mmol TE per liter) and increased with exercise-related energy expenditure (P = 0.007). Transthyretin cysteinylation rate differed between the groups, with the highest rate of protein modifications in moderately active subjects (P = 0.007). Conclusions: Results suggest that if the nutritional choice of athletes is well balanced, enough antioxidants are provided to meet recommended amounts. Moreover, regular exercise increases blood antioxidant capacity in young athletes, whereas chronic exercise was not shown to promote protein modifications. Thus, in young athletes who are sufficiently supplied with antioxidants, beneficial effects of exercise on antioxidant status rather than on oxidative stress may be anticipated. Y1 - 2010 UR - http://www.ms-se.com/ U6 - https://doi.org/10.1249/Mss.0b013e3181c74f7b SN - 0195-9131 ER - 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 -