Neuromuscular control of goal-directed ankle movements differs for healthy children and adults
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The purpose was to compare neuromuscular control of rapid ankle goal-directed movements in healthy preadolescent children and young adults.
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.
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.
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.
KeywordsPre-adolescence Variability Accuracy EMG Lower limb
Maximum voluntary contraction
The authors would like to thank Hannah Mora, Ericka Miller, Brittany Forster, and Mark Costanzo for their help with data collection. This study was supported by R01 AG031769 to Evangelos A. Christou.
Conflict of interest
No conflict of interest for any of the co-authors.
- Eckert HM (ed) (1987) Motor development, 3rd edn. Benchmark Press, IndianapolisGoogle Scholar
- Fox EJ, Kwon M, Chen Y-T, Costanzo M, Mora H, Sowalsky K, Christou EA (2012) Altered agonist muscle activation explains impaired endpoint accuracy during goal-directed movements of the ankle in children. Society for Neuroscience, New OrleansGoogle Scholar
- Gabbard C (ed) (2008) Lifelong motor development. Pearson Benjamin Cummings, San FranciscoGoogle Scholar
- Gogtay N, Giedd JN, Lusk L, Hayashi KM, Greenstein D, Vaituzis AC, Nugent TF 3rd, Herman DH, Clasen LS, Toga AW, Rapoport JL, Thompson PM (2004) Dynamic mapping of human cortical development during childhood through early adulthood. Proc Natl Acad Sci USA 101:8174–8179PubMedCentralPubMedCrossRefGoogle Scholar
- Grosset JF, Mora I, Lambertz D, Perot C (2007) Changes in stretch reflexes and muscle stiffness with age in prepubescent children. J Appl Physiol 102:2352–2360Google Scholar
- Grosset JF, Canon F, Perot C, Lambertz D (2014) Changes in contractile and elastic properties of the triceps surae muscle induced by neuromuscular electrical stimulation training. Eur J Appl Physiol. doi: 10.1007/s00421-014-2871-4