Changes in kinematic synergy in older adults during walking: A two-year follow-up study

• Published in: Gait & posture Vol. 96; pp. 244 - 250
• Main Authors: Yamagata, Momoko, Tateuchi, Hiroshige, Shimizu, Itsuroh, Ichihashi, Noriaki
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01.07.2022
• Subjects: Aged; Aging; Biomechanical Phenomena; Center of mass; Follow-Up Studies; Gait; Gait - physiology; Humans; Longitudinal Studies; Uncontrolled manifold; Walking - physiology; Walking Speed; Aging; Uncontrolled manifold; Gait; Center of mass
• ISSN: 0966-6362; 1879-2219
• DOI: 10.1016/j.gaitpost.2022.05.030

A well-controlled center of mass (CoM) in a coordinated segmental manner is required during gait. A synergy index that quantifies the strength of the synergistic control of the body segments that control the CoM can be evaluated using uncontrolled manifold (UCM) analysis. Several studies have compared the synergy index between older and younger adults; however, contradictory results have been found regarding age-related changes in the synergy index. Moreover, no study has investigated these changes longitudinally. To evaluate age-related changes in the synergy index to control the CoM during gait in a longitudinal study. Twenty-five older adults participated at a baseline visit. The gait task at the two-year follow-up was completed by 16 older adults. Participants walked on a 6-m walkway at baseline and the two-year follow-up, and kinematic data were collected. Using UCM analysis, the synergy indices controlling CoM in the mediolateral and vertical directions were evaluated at baseline and follow-up. We also evaluated the Timed Up and Go (TUG) test and the strength of the knee extensor at both periods. We found that TUG was significantly slower at follow-up; however, no difference was found in muscle strength. The synergy index in the mediolateral direction increased significantly after two years; such increases were found in individuals with decreased gait speed. This study showed that changes in gait patterns, including decreasing gait speed and increasing segmental coordination, may be important for gait with appropriate postural control relative to the environment and dynamic stability of the body in individuals with low functional mobility. •A well-controlled center of mass by segmental coordination is required during gait.•We evaluated age-related changes in synergistic control for center of mass.•Synergy indices quantify the strength of synergistic body segment control.•The synergy index to control the mediolateral center of mass was increased with aging.•The increase in the synergy index was related to slow gait speed.