Which muscles compromise human locomotor performance with age?

Area of Science:

• Biomechanics
• Gerontology
• Human Locomotion

Background:

• Aging causes a decline in human locomotor performance.
• The specific muscle groups responsible for this decline are not fully understood.

Purpose of the Study:

• To compare joint moments and powers generated by lower limb muscles across different age groups (young, middle-aged, old).
• To investigate how these changes vary with different locomotion types: walking, running, and sprinting.

Main Methods:

• Participants: young, middle-aged, and old adults.
• Locomotion tasks: self-selected walking, running at 4 m/s, and maximal sprinting.
• Measurements: joint moments and powers of lower limb muscles.

Main Results:

• Age-related deficits in ankle plantarflexor moment and power worsen with increased locomotion intensity.
• Older adults increase knee and hip extensor power during walking and running compared to younger adults.
• During sprinting, young adults show greater ankle and hip power, but not knee power, compared to older adults.

Conclusions:

• Ankle propulsive deficits are the primary contributor to age-related locomotor decline.
• Reduced hip muscle output, rather than knee muscle output, limits sprinting performance in older individuals.