Maximal Strength Training Increases Metabolic Energy Expenditure in Sedentary Adults Classified as Obese

Background: Metabolic adaptations reduce resting and non-resting energy expenditure to account for approximately 120 kcal/day. Weight loss promotes greater skeletal muscle efficiency, reducing the energy cost of physical activity and is correlated with declines in skeletal muscle glucose oxidation. Maximal Strength Training (MST) has the potential to upregulate glucose utilization and may offset these metabolic adaptations. Objective: To determine if MST offsets markers of metabolic adaptation by increasing resting and non-resting energy expenditure in sedentary individuals classified as obese. Methods: Five (5) participants (2 females, 3 males), ages 18-35 years, with obesity (BMI 30–45 kg/m2) were enrolled in an 8-week MST intervention. Participants completed 3 MST sessions per week on non-consecutive days. Resting Energy Expenditure (REE) via indirect calorimetry and Skeletal Muscle Work Efficiency (SME) via graded exercise cycle ergometer test were assessed pre and post intervention. Results: REE (in kcal/kg FFM/24hrs) increased from 30.51 at baseline to 37.37 post (a 22.48% increase, P=0.02) with no significant changes in Body Fat (BF) or FFM. Skeletal Muscle Efficiency (SME) calculated as (watts converted to kcal/min)/ [energy expended (kcal/min) – resting energy expenditure (kcal/min) adjusted for fat-free mass) trended towards a significant decrease at 25 W (-6.51%, P=0.435) and at 50 W (-4.01%, P=0.579). Conclusions: These results suggest that an 8-week MST intervention can significantly increase REE in individuals classified as obese and shows trends towards decreasing SME at low intensity exercise. Therefore, MST may be a useful strategy to attenuate metabolic compensation