The effect of short‐duration resistance training on insulin sensitivity and muscle adaptations in overweight men

Objectives: The aim of the current study was to investigate the effects of six weeks of resistance exercise training, compromised of one set of each exercise to voluntary failure, on i) insulin sensitivity and ii) the time-course of adaptations in muscle strength/mass. Methods: Ten overweight men (age: 36 ± 8 years; height 175 ± 9 cm; weight 89 ± 14 kg; BMI 29 ± 3 kg.m2) were recruited to the study. Resistance exercise training involved three sessions per week for six weeks. Each session involved one set, of nine exercises, performed at 80% of 1 repetition maximum (1RM) to volitional failure. Sessions lasted 15-20 minutes. Oral glucose tolerance tests were performed at baseline and post intervention. Vastus lateralis muscle thickness, knee extensor maximal isometric torque and rate of torque development (RTD – measured between 0-50ms, 0-100ms, 0-200ms and 0-300ms) were measured at baseline, each week of the intervention, and after the intervention. Results: Resistance training resulted in a 16.3 ± 18.7% (P<0.05) increase in insulin sensitivity (Cederholm index). Muscle thickness, maximal isometric torque and 1RM increased with training ending the intervention 26.9 ± 8.3%, 10.3 ± 2.5%, 18.3 ± 4.5 higher (P<0.05 for both) than baseline, respectively. RTD50ms and 100ms, but not RTD200ms and 300ms, increased (P<0.05) over the intervention period. Conclusions: Six weeks of single set resistance exercise to failure results in improvements in insulin sensitivity and increases in muscle size and strength in young overweight men.