Faculty Advisor

Stock, Matt

Publication Date

Spring 2018

Abstract

Background: Research has typically focused on the association between the age-related loss of skeletal muscle mass known as sarcopenia, rather than the age-related loss of muscle strength known as dynapenia with functional decline and disability. Literature has shown that the commonly assumed equivalence between muscle mass and strength is not the case.

Objectives: To determine if leg lean mass, squat peak strength, and rate of force development predict short- and long distance fast gait speed in younger versus older adults and whether predictability was similar for different age groups

Design: Comparison

Setting: Texas Tech Lab

Participants: Twenty-four younger (12 men, 12 women; median age = 21 years; mean ± SD BMI = 23.4 ± 4.0 kg/m2) and 22 older (11 men, 11 women; median age = 72; BMI = 26.6 ± 3.2) adults participated.

Measurements: Fast gait speed was assessed at 10 and 400-m distances. Leg lean mass was quantified with dual X-ray absorptiometry (DEXA). Isometric squat peak force and the peak rate of force development were tested with a 60° knee joint angle using an isokinetic squat device. Separate stepwise regression analyses for each age group were used to assess the predictability of the independent variables on 10 and 400-m gait speed

Results: For the younger adults, none of the independent variables were worthy predictors. For the older adults, peak force was a significant predictor of both 10-m (R2 = 0.257; adjusted R2 = 0.220; P = 0.016) and 400-m (R2 = 0.239; adjusted R2 = 0.200; P = 0.021) fast gait speed

Conclusion: In older adults, lower-extremity muscle strength becomes increasingly important for regulating fast gait speed, whereas muscle mass is not of value.

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