The purpose of this study was to determine if exercise prescriptions differing in volume or intensity also differed in their ability to retain insulin sensitivity during an ensuing period of training cessation. Sedentary, overweight/obese subjects were assigned to one of three, eight-month exercise programs: 1) Low Volume/Moderate Intensity [equivalent of ~12 miles/wk, 1200 kcal/wk at 40-55% VO₂peak, 200 min exercise/wk]; 2) Low Volume/Vigorous Intensity [~12 miles/wk, 1200 kcal/wk at 65-80% VO₂peak, 125 min/wk]; and 3) High Volume/Vigorous Intensity [~20 miles/wk, 2000 kcal/wk at 65-80% VO₂peak, 200 min/wk]. Insulin sensitivity (intravenous glucose tolerance test, S_I) was measured when sedentary and at 16-24 h and 15 d following the final training bout. S_I increased with training compared to the sedentary condition (P 0.05) at 16-24 h with all of the exercise prescriptions. S_I decreased to sedentary, pre-training values after 15 d of training cessation in the Low Volume/Vigorous Intensity group. In contrast, at 15 d S_I was significantly elevated compared to sedentary (P 0.05) in the prescriptions utilizing 200 min/wk (Low Volume/Moderate Intensity, High Volume/Vigorous Intensity). In the High Volume/Vigorous Intensity group, indices of muscle mitochondrial density followed a pattern paralleling insulin action by being elevated at 15 d compared to pre-training; this trend was not evident in the Low Volume/Moderate Intensity group. These findings suggest that in overweight/obese subjects, a relatively chronic persistence of enhanced insulin action may be obtained with endurance-oriented exercise training; this persistence, however, is dependent upon characteristics of the exercise training performed.