Older but not younger adults rely on multijoint coordination to stabilize the swinging limb when performing a novel cued walking task

Motor flexibility to stabilize the toe position during obstacle crossing in older adults: an investigation using an uncontrolled manifold analysis

“…The present study investigated motor flexibility for stabilizing the toe position during obstacle crossing in older adults and its correlation with the magnitude of clearance height. The present study was designed to extend the knowledge obtained by Yamagata et al (11). There were two main differences between Yamagata et al and the present study.…”

“…The first hypothesize was that the synergy index (ΔVz) is lower in older adults than in younger adults with both the leading and trailing limbs in the pre-crossing phase including at the moment of obstacle crossing. The second hypothesis was that, consistent with the findings of Yamagata et al (11), higher foot elevation (i.e., a conservative strategy) is associated with less motor flexibility. Specifically, we expected that foot clearance (equivalent to foot elevation), calculated as the distance between the toe and the obstacle, was negatively correlated with the ΔVz with both the leading and trailing limbs.…”

“…In other studies, older adults exhibited a higher foot elevation while stepping over an obstacle (2,6,7). Although such behavior, which has been referred to as "a conservative strategy" (6,7) is helpful to avoid tripping as a result of creating a greater safety margin, this behavior could also result in destabilization, which could also lead to falls (8)(9)(10)(11). These findings suggest that not only much lower foot elevation but also much higher foot elevation during stepping over an obstacle of height could lead to falls due to tripping or destabilization, respectively.…”

“…Recently, Yamagata et al (11) reported an age-related decrease in motor flexibility to maintain stability during stepping over an obstacle and its relation to higher foot elevation. In Yamagata et al, healthy older adults walked and crossed an obstacle with a fixed height (8 cm).…”

Effects of sensory manipulations on locomotor adaptation to split-belt treadmill walking in healthy younger and older adults

“…Evidence of motor adaptability has also been observed kinematically during more complicated walking tasks. Specifically, during “cued” walking on a treadmill - where individuals must place their feet on targets specified by lighted cues - older adults exhibit high levels of task-oriented inter-segment covariation from step to step, indicating the use of “motor flexibility” ( Rosenblatt, Eckardt, Kuhman, & Hurt, 2020 ). The convergence of results across a variety of experimental and analytical approaches strengthens the notion that healthy aging does not limit motor adaptability, at least as it relates to locomotion.…”