PURPOSE: The purpose was to compare neuromuscular control of rapid ankle goal-directed movements in healthy preadolescent children and young adults. METHODS: Ten young adults (20.0 ± 0.9 years) and ten children (9.5 ± 0.7 years) attempted to accurately match the peak displacement of the foot to a spatiotemporal target with an ankle dorsiflexion movement. The targeted displacement was 9° of ankle dorsiflexion, and the targeted time was 180 ms. Surface electromyograms (EMGs) were recorded from the tibialis anterior (TA; agonist) and soleus (SOL; antagonist) muscles. Ankle movement control was quantified with endpoint accuracy and variability. The activation of the involved muscles was quantified with an EMG burst analysis. RESULTS: Children exhibited decreased endpoint accuracy and control compared with young adults, as indicated by greater endpoint errors (47.6 ± 15.2 vs. 25.8 ± 9.0%) and position variability (29.5 ± 5.7 vs. 15.2 ± 6.1 %). In addition, children exhibited differences in muscle activation, as evidenced by greater TA (53.2 ± 19.1 vs. 33.0 ± 19.0%) and SOL (19.9 ± 12.0 vs. 9.6 ± 5.4%) amplitudes of EMG burst, shorter TA duration (251.3 ± 43.6 vs. 296.1 ± 27.6%), and greater variability in the activation of these muscles. The endpoint error (R (2) = 0.7) and position variability (R (2) = 0.67) were predicted from the TA burst amplitude variability and TA burst duration. CONCLUSION: The differences in muscle activation and deficient control of rapid goal-directed ankle movements exhibited by children are likely due to their incomplete development of higher centers.
PURPOSE: The purpose was to compare neuromuscular control of rapid ankle goal-directed movements in healthy preadolescent children and young adults. METHODS: Ten young adults (20.0 ± 0.9 years) and ten children (9.5 ± 0.7 years) attempted to accurately match the peak displacement of the foot to a spatiotemporal target with an ankle dorsiflexion movement. The targeted displacement was 9° of ankle dorsiflexion, and the targeted time was 180 ms. Surface electromyograms (EMGs) were recorded from the tibialis anterior (TA; agonist) and soleus (SOL; antagonist) muscles. Ankle movement control was quantified with endpoint accuracy and variability. The activation of the involved muscles was quantified with an EMG burst analysis. RESULTS:Children exhibited decreased endpoint accuracy and control compared with young adults, as indicated by greater endpoint errors (47.6 ± 15.2 vs. 25.8 ± 9.0%) and position variability (29.5 ± 5.7 vs. 15.2 ± 6.1 %). In addition, children exhibited differences in muscle activation, as evidenced by greater TA (53.2 ± 19.1 vs. 33.0 ± 19.0%) and SOL (19.9 ± 12.0 vs. 9.6 ± 5.4%) amplitudes of EMG burst, shorter TA duration (251.3 ± 43.6 vs. 296.1 ± 27.6%), and greater variability in the activation of these muscles. The endpoint error (R (2) = 0.7) and position variability (R (2) = 0.67) were predicted from the TA burst amplitude variability and TA burst duration. CONCLUSION: The differences in muscle activation and deficient control of rapid goal-directed ankle movements exhibited by children are likely due to their incomplete development of higher centers.
Authors: Bareket Falk; Charlotte Usselman; Raffy Dotan; Laura Brunton; Panagiota Klentrou; Jay Shaw; David Gabriel Journal: Appl Physiol Nutr Metab Date: 2009-08 Impact factor: 2.665