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 -2 ) or a control group (CONT) (13.7 ± 0.4 yrs; BMI: 32.6 ± 1.6 kg.m -2 ). 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 (VO 2 peak) defined as VO 2 peak per kg of body mass (mL.min -1 kg -1 ) or by VO 2 peak per kg of lean body mass (mL.min -1 LBM -1 ) and body composition was assessed by dual-energy X-ray absorptiometry. SIT intervention led to a significant and large between-group difference in VO 2 peak (p = 0.004; η 2  = 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.