Muscle power deficiencies in fallers with lower-limb loss.

Area of Science:

• Biomechanics
• Kinesiology
• Rehabilitation Science

Background:

• Impaired muscle strength is a known risk factor for falls in clinical populations.
• Limited research exists on muscle power output in individuals with lower-limb loss and high fall risk.

Purpose of the Study:

• To investigate the effects of contraction speed on lower-extremity muscle power.
• To compare muscle power across three groups: control, nonfallers, and fallers with lower-limb loss.

Main Methods:

• Recruited 13 adults without lower-limb loss and 15 adults with lower-limb loss.
• Measured bilateral average power for hip, knee, and ankle at 60°/s and 120°/s using a Biodex™ dynamometer.
• Utilized a mixed-model ANOVA to analyze group and speed effects on muscle power.

Main Results:

• Fallers with lower-limb loss exhibited significantly weaker sound limb hip extensor/flexor muscles compared to nonfallers.
• Fallers were weaker than controls in sound limb hip and affected limb knee muscles; nonfallers' sound hip power was similar to controls.
• Muscle power showed significant speed effects in controls and nonfallers, but only in the sound knee extensors of fallers.

Conclusions:

• Sound hip muscle weakness may increase fall risk in individuals with lower-limb loss.
• Fallers with lower-limb loss demonstrated an inability to adapt muscle power output to higher velocities, unlike controls and nonfallers.
• High-velocity power training could potentially mitigate fall risk in this population.