Excess body weight and gait influence energy cost of walking in older adults.

Abstract

The objective of this investigation is to study how excess body weight influences the energy cost of walking (Cw) and determine whether overweight and obese older adults self-select stride frequency to minimize Cw. Using body mass index (BMI), men and women between the ages of 65 and 80 yr were separated into normal weight (NW, BMI ≤24.9 kg·m(-2), n = 13) and overweight-obese groups (OWOB, BMI ≥25.0 kg·m(-2), n = 13). Subjects walked at 0.83 m·s on an instrumented treadmill that recorded gait parameters and completed three 6-min walking trials; at a preferred stride frequency (PSF), at +10% PSF, and at -10% PSF. Cw was determined by indirect calorimetry. Repeated-measures ANOVA was used to compare groups, and associations were tested with Pearson correlations, α = 0.05. OWOB had 62% greater absolute Cw (301 ± 108 vs 186 ± 104 J·m, P < 0.001) and 20% greater relative Cw(kg) (3.48 ± 0.95 vs 2.91 ± 0.94 J·kg(-1)·m(-1), P = 0.046) than NW. Although PSF was not different between OWOB and NW (P = 0.626), Cw was 8% greater in OWOB at +10% PSF (P < 0.001). At PSF, OWOB spent less time in single-limb support (33.1% ± 1.5% vs. 34.9% ± 1.6 % gait cycle, P = 0.021) and more time in double-limb support (17.5% ± 1.6% vs 15.4% ± 1.4% gait cycle, P = 0.026) than NW. In OWOB, at PSF, Cw was correlated to impulse (r = -0.57, P = 0.027) and stride frequency (r = 0.51, P = 0.046). Excess body weight is associated with greater Cw in older adults, possibly contributing to reduced mobility in overweight and obese older persons.