Document Detail


Age-related differences in adaptation during childhood: the influences of muscular power production and segmental energy flow caused by muscles.
MedLine Citation:
PMID:  17019608     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Acquisition of skillfulness is not only characterized by a task-appropriate application of muscular forces but also by the ability to adapt performance to changing task demands. Previous research suggests that there is a different developmental schedule for adaptation at the kinematic compared to the neuro-muscular level. The purpose of this study was to determine how age-related differences in neuro-muscular organization affect the mechanical construction of pedaling at different levels of the task. By quantifying the flow of segmental energy caused by muscles, we determined the muscular synergies that construct the movement outcome across movement speeds. Younger children (5-7 years; n = 11), older children (8-10 years; n = 8), and adults (22-31 years; n = 8) rode a stationary ergometer at five discrete cadences (60, 75, 90, 105, and 120 rpm) at 10% of their individually predicted peak power output. Using a forward dynamics simulation, we determined the muscular contributions to crank power, as well as muscular power delivered to the crank directly and indirectly (through energy absorption and transfer) during the downstroke and the upstroke of the crank cycle. We found significant age x cadence interactions for (1) peak muscular power at the hip joint [Wilks' Lambda = 0.441, F(8,42) = 2.65, p = 0.019] indicating that at high movement speeds children produced less peak power at the hip than adults, (2) muscular power delivered to the crank during the downstroke and the upstroke of the crank cycle [Wilks' Lambda = 0.399, F(8,42) = 3.07, p = 0.009] indicating that children delivered a greater proportion of the power to the crank during the upstroke when compared to adults, (3) hip power contribution to limb power [Wilks' Lambda = 0.454, F(8,42) = 2.54, p = 0.023] indicating a cadence-dependence of age-related differences in the muscular synergy between hip extensors and plantarflexors. The results demonstrate that in spite of a successful performance, children construct the task of pedaling differently when compared to adults, especially when they are pushed to their performance limits. The weaker synergy between hip extensors and plantarflexors suggests that a lack of inter-muscular coordination, rather than muscular power production per se, is a factor that limits children's performance ranges.
Authors:
Thomas Korff; Jody L Jensen
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Experimental brain research     Volume:  177     ISSN:  0014-4819     ISO Abbreviation:  Exp Brain Res     Publication Date:  2007 Mar 
Date Detail:
Created Date:  2007-09-20     Completed Date:  2007-10-31     Revised Date:  2013-12-13    
Medline Journal Info:
Nlm Unique ID:  0043312     Medline TA:  Exp Brain Res     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  291-303     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological / physiology*
Adult
Age Factors
Aging / physiology*
Algorithms
Bicycling / physiology
Biomechanical Phenomena
Child
Child, Preschool
Energy Transfer
Female
Humans
Lower Extremity / physiology
Male
Muscle, Skeletal / physiology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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