Lower-limb muscle function in healthy young and older adults across a range of walking speeds

• Published in: Gait & posture 2022-05, Vol.94, p.124-130
• Main Authors: Lim, Yoong Ping, Lin, Yi-Chung, Pandy, Marcus G.
• Format: Article
• Language: English
• Subjects: Aged; Balance; Biomechanical Phenomena; Elderly gait; Gait - physiology; Humans; Models, Biological; Muscle, Skeletal - physiology; Musculoskeletal model; Progression; Support; Walking - physiology; Walking Speed
• ISSN: 0966-6362; 1879-2219
• DOI: 10.1016/j.gaitpost.2022.03.003

Previous studies have compared the functional roles of the individual lower-limb muscles when healthy young and older adults walk at their self-selected speeds. No age-group differences were observed in ankle muscle forces and ankle muscle contributions to support and progression. However, older adults displayed higher gluteus maximus (hip extensor) muscle forces and greater contributions to support during early stance. There are no data that describe the functions of the individual lower-limb muscles in healthy older adults for walking at speeds other than the self-selected speed. How does walking speed affect the functional roles of the individual lower-limb muscles in healthy older adults? Three-dimensional gait data were recorded for 10 healthy young and 10 healthy older adults walking at slow, normal, and fast speeds (0.7 m/s, 1.4 m/s, and 1.7 m/s, respectively). Both groups walked at the same speed at each condition. The experimental data were combined with a full-body musculoskeletal model to calculate and compare muscle forces and muscle contributions to the vertical, fore-aft, and mediolateral ground reaction forces (support, progression, and balance, respectively) in both groups. Lower-limb muscle function was similar in young and older adults when both groups walked at the same speed at each condition. The same five muscles - gluteus maximus, gluteus medius, vasti, gastrocnemius, and soleus – contributed most significantly to support, progression, and balance in both groups at all speeds. However, gluteus maximus generated greater support and braking forces during early stance and gastrocnemius contributed less to forward propulsion during late stance at all speeds in the older group. These results provide further insight into the functional roles of the individual lower-limb muscles of older adults during walking and could inform the design of exercise programs aimed at improving support and balance in those at risk of falling. •Muscle function was similar in young and older adults across different gait speeds.•The same muscles contributed to support, progression and balance in both groups.•Compensatory mechanisms involving the hip and ankle muscles were also observed.•The hip extensors generated more support during early stance in older adults.•The ankle plantarflexors contributed less to forward propulsion in the older group.