Plantarflexor passive-elastic properties related to BMI and walking performance in older women
Abstract
The objective of this study was to examine the influence of BMI on the passive-elastic properties of the ankle plantarflexors in older women. Twenty-three women, 65–80 yr, were separated into normal weight (NW, BMI < 25.0 kg m−2, n = 11) and overweight-obese (OW, BMI ≥ 25.0 kg m−2, n = 12) groups. Resistive torque of the ankle plantarflexors was recorded on an isokinetic dynamometer by passively moving the ankle into dorsiflexion. Stiffness, work absorption, and hysteresis were calculated across an ankle dorsiflexion angle of 10–15°. Maximal plantarflexor strength was assessed, then participants walked at maximal speed on an instrumented gait analysis treadmill while muscle activation (EMG) was recorded. Plantarflexor stiffness was 34% lower in OW (26.4 ± 12.7 Nm rad−1) than NW (40.0 ± 15.7 Nm rad−1, p = 0.032). Neither work absorption nor hysteresis were different between OW and NW. Stiffness per kg was positively correlated to strength (r = 0.66, p < 0.001), peak vertical ground reaction force during walking (r = 0.72, p < 0.001), weight acceptance rate of force (r = 0.51, p = 0.007), push-off rate of force (r = 0.41, p = 0.026), maximal speed (r = 0.61, p = 0.001), and inversely correlated to BMI (r = −0.61, p = 0.001), and peak plantarflexor EMG (r = −0.40, p = 0.046). Older women who are OW have low plantarflexor stiffness, which may limit propulsive forces during walking and necessitate greater muscle activation for active force generation.
Department
Kinesiology
Publication Date
3-1-2017
Journal Title
Gait & Posture
Publisher
Elsevier
Digital Object Identifier (DOI)
Document Type
Article
Recommended Citation
D.P. LaRoche. (2017) Plantarflexor passive-elastic properties related to BMI and walking performance in older women. Gait & Posture. 53:55-60.
Rights
© 2017 Elsevier Inc. All rights reserved.