Purpose was to determine effects resistance training/weight loss induced changes in muscular strength and flexibility have on net walking oxygen uptake (netVO(2)). 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). NetVO(2) 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 netVO(2). Decreases in walking and grade netVO(2) were independently and positively related to increased knee extension strength and decreased knee extensor and plantar flexor flexibility.