PurposeWe examined the possibility that old adults use flexibility in joint coordination
as a compensatory mechanism for the age-related decline in muscle strength when performing
the sit-to-stand (STS) task repeatedly under high force and balance demands.MethodYoung
(n=14, 22.42.1) and old (n=12, 703.2) healthy adults performed repeated STSs under
high and low force and balance demands. The balance demand was manipulated by reducing
the base of support and the force demand by increasing body weight with a weight vest.
Uncontrolled manifold analysis was used to quantify age differences in motor flexibility.Results
p id= Par3 While there were age-typical differences in kinematic STS strategies, flexibility
in joint coordination was independent of age and task difficulty during repeated STSs.Discussion
p id=Par4That simple manipulations of force and balance demands did not affect flexibility
in joint coordination in old and young adults suggests that motor flexibility acts
as a compensatory mechanism only at the limits of available muscle strength and balance
abilities during STS movements. Intervention studies should identify how changes in
specific neuromuscular functions affect flexibility in joint coordination during activities
of daily living such as STS.