Aging-Related Cocontraction Effects During Ankle Strategy Balance Recovery Following Tether Release in Women

ABSTRACT

Increased antagonistic muscle activation during balance recovery has been documented during proprioceptive reliant responses in older adults. The authors examined ankle muscle cocontraction levels in young and older adults during balance recovery from a tether-release-induced, vestibular-input-reliant perturbation. Nine healthy young adult and 9 older women without history of falls performed maximum isometric plantar flexion and dorsiflexion trials followed by balance recovery trials using the ankle strategy. Surface electromyography data normalized to isometric conditions were analyzed during the 100 ms prior to release, the 50 ms immediately after release, and the 100-ms epochs from 100–400 ms following release. No differences existed in gastrocnemius and soleus activity levels (p > .05), though antagonistic tibialis anterior activity was greater in the older adults during the 300–400 ms epoch (young: 23.5 ± 5.8%, older: 38.7 ± 9.4%; p = .001). Vestibular-dominated perturbations may increase antagonistic activity during the recovery phase in older adults, inhibiting efficient balance recovery during proprioceptive and vestibular reliant perturbations.

Keywords:

• ankle strategy
• cocontraction
• tether-release
• vestibular input

ACKNOWLEDGMENTS

This publication was supported by Grant No. R49/CCR811509 from the Centers for Disease Control and Prevention. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention. None of the authors has any financial and personal relationships with other individuals or organizations that could inappropriately influence the work.