Effect of supervised sprint interval training on cardiorespiratory fitness and body composition in adolescent boys with obesity.

This study examined the effect of a supervised 12-week sprint interval training (SIT) on cardiorespiratory fitness (CRF) and body composition in adolescent boys with obesity. Twenty-eight adolescents with obesity were allocated to either an intervention group (SIT) (13.1 ± 0.3 yrs; body mass index [BMI]: 30.3 ± 0.9 kg.m) or a control group (CONT) (13.7 ± 0.4 yrs; BMI: 32.6 ± 1.6 kg.m). The SIT group performed 4-6 × 30s "all-out" cycling bouts, interspersed with 4 min of recovery 3 days a week for 12 weeks. CRF was measured by direct peak oxygen consumption (VOpeak) defined as VOpeak per kg of body mass (mL.minkg) or by VOpeak per kg of lean body mass (mL.minLBM) and body composition was assessed by dual-energy X-ray absorptiometry. SIT intervention led to a significant and large between-group difference in VOpeak (p = 0.004; η = 0.29). Although SIT group had a significant reduction in body fat percentage (BF%) (from 41.1 ± 1.3% to 39.2 ± 1.5%; p = 0.006), there were no between-group differences in the change of the pre- and post-measures in BF% (p = 0.067). In conclusion, 12-week SIT is effective in increasing CRF and decreasing BF% in adolescent boys with obesity.