Associations between muscle mechanical function, muscle quality and gait speed in older adults

Introduction
Muscle quality is the ability to generate muscle strength relative to muscle size (MSQ). Muscle power (force*velocity)
declines at faster rate than strength with aging, and muscle power quality (MPQ: power dived by muscle size) may be a
stronger predictor than muscle strength or power alone as well as MSQ for gait performance. This study aims at
investigating the predictive ability of muscle strength and power, MSQ and MPQ on short- and long-distance gait speed.
Methods
Sixty-five older adults (82.5±4.8 years) were assessed for maximum isometric single leg press strength (Newtonkg body
weight), single leg press power (Nottingham Power Rig) (Wattkg body weight) and for fat-free mass on a full-body DXA
scanning. MSQ and MPQ were calculated by dividing strength and power by lower-body fat-free mass (FFM). Maximum gait
speed was measured during a 10m test and 2-minute walk test.
Results
Muscle power and strength alone were associated with 10m (R2=0.39, R2=0.33, respectively pR2=0.33, respectively, p2-minwt (R2=0.31, R2=0.22, respectively) (pConclusion
Muscle power normalized by body weight was the strongest predictor of short- and long-distance gait speed. Muscle power
quality and muscle strength quality provided weaker associations with gait speed for both gait distances compared to
strength and power alone. Muscle power quality has a stronger association to gait speed than muscle strength quality on
both short- and long gait distance.