Flexibility in joint coordination remains unaffected by force and balance demands in young and old adults during simple sit-to-stand tasks

Abstract

Purpose We 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. Method Young ( n = 14, 22.4 ± 2.1) and old ( n = 12, 70 ± 3.2) 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 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 That 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.

Search Strategies in the Perceptual-Motor Workspace and the Acquisition of Coordination, Control, and Skill

“…For instance, Latash (2010) has provided examples that in the middle stage of learning the UCM-like distribution might be more pronounced than when individuals are more proficient. Also, special populations demonstrate higher or equal UCM-like distribution than their healthy (or younger) peers (Black et al, 2007; Golenia et al, 2018; Greve et al, 2019). Furthermore, many of our experiments when analyzed for each individual do not show increased UCM and decreased ORT as would be expected (non-published results).…”

Effect of Instrument-Assisted Soft Tissue Mobilization on Ankle of Range of Motion and Balance in Older Women: A Preliminary Study

“…The older need balance to perform daily tasks such as walking quickly and sit-to-stand [27]. However, due to changes to the sensorimotor and neuromuscular system of the ankle and restricted ankle ROM, the older have decreased performance in static and dynamic postural, and these changes may increase the risk of falls [3,28].…”

Individuals with patellofemoral pain syndrome have altered inter-leg force coordination

“…The between-group differences in motor abundance in all three axes reduced as hopping frequency increased. This suggests that individuals with PFPS may have a "reserve capacity" to harness more motor abundance when required [10,24]. As hopping frequency increases, the body shifts intra-leg control of the vertical GRF from a strategy involving the hip-knee-ankle joints, to an independent ankle strategy [8].…”

“…We hypothesized that individuals with PFPS would exhibit a smaller index of motor abundance in the regulation of the vertical, AP, and ML GRFs compared to healthy individuals. Prior studies have shown a capacity for humans to harness greater motor abundance as task intensity increases [10] . Hence, we hypothesized that motor abundance between individuals with and without PFPS will become more similar at faster than slower hopping intensities.…”