Aging modifies joint power and work when gait speeds are matched

Area of Science:

• Biomechanics
• Gerontology
• Human Movement Science

Background:

• Ankle joint power generation is known to decrease in older adults during gait.
• Compensatory mechanisms in the hip and knee joints are not well understood.

Purpose of the Study:

• To investigate the effects of aging on lower limb joint power and work during gait.
• To understand how older adults compensate for reduced ankle power.

Main Methods:

• Gait patterns of 8 older adults (OG) and 12 young adults (YG) were recorded at matched speeds (1.0, 1.3, 1.6 m/s).
• Lower limb joint power and work were analyzed and compared between groups.

Main Results:

• Older adults generated 17% less ankle power and 21% less ankle work.
• Older adults showed increased hip work (46%) and peak power at the hip (30%, 16%) and knee (30%, 19%).
• These changes were associated with reduced ankle plantar-flexion and increased hip flexion and anterior pelvic tilt.

Conclusions:

• Older adults rely more on hip flexors for leg propulsion when ankle plantar-flexor function is diminished.
• This compensatory strategy involving hip and knee joints may explain gait changes associated with aging.