Increased strength and decreased flexibility are related to reduced oxygen cost of walking

Purpose was determine effects resistance training/weight loss induced changes in muscular strength and flexibility have on net walking oxygen uptake (netVO₂). Sixty-seven premenopausal women lost 12 kg. Before weight loss subjects were assigned to diet (WL) or diet/3 days per week resistance training (WLRT). Resting energy expenditure, oxygen uptake while walking at 4.84 km h⁻¹ on the flat and up 2.5% grade, isometric knee extension strength, and flexibility of the knee extensors and plantar flexors were measured. Strength increased in WLRT (+36 N) but not in WL (−24 N). NetVO₂ decreased significantly while flat walking (7.3%) and 2.5% grade walking (5.7%) in WLRT, but not in WL. Delta strength was negatively while delta knee extensor and plantar flexor flexibility were positively related to delta netVO₂. Decreases in walking and grade netVO₂ were independently and positively related to increased knee extension strength and decreased knee extensor and plantar flexor flexibility.