Not all is lost: Old adults retain flexibility in motor behaviourduring sit-to-stand

Greve, C. (Christian) (2013) Not all is lost: Old adults retain flexibility in motor behaviourduring sit-to-stand. thesis, Human Movement Sciences.

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Abstract

Sit-to-stand is a fundamental activity of daily living, which becomes increasingly difficult with advancing age. The severe loss of leg strength requires old adults to change the way they stand up from a chair in order to maintain stability. Here we examine whether old compared to young adults prioritize control of different performance variables and whether there are age-related differences in the use of available motor flexibility. We applied the uncontrolled manifold analysis to decompose trial-to-trial variability in joint kinematics into variability stabilizing task-important performance variables and variability destabilizing task-important performance variables. Comparing the amount of variability stabilizing a performance variable with the amount of variability destabilizing a performance variable enables to identify the variable of primary importance for the task. We measured maximal isometric voluntary strength in the ankle dorsiflexors and knee and hip flexors and extensors of the right leg. Independent of age and muscle strength, old and young adults similarly prioritized stability of the ground reaction force vector during sit-to-stand. Old compared to young adults also employed a more flexible motor behaviour, stabilizing ground reaction forces during sitto-stand. We concluded that freeing those degrees of freedom that stabilize task-important performance variables is a strategy used by the aging neuromuscular system to compensate for strength deficits.

Item Type:	Thesis (Thesis)
Supervisor name:	Bongers, Raoul M and Hortobagyi, Tibor and Center for Human Movement Science, University of Groningen
Supervisor name:	Zijlstra, Wiebren and Institute of Movement and Sports Gerontology, German Sport U
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 11:06
Last Modified:	25 Jun 2020 11:06
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/2626

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