Acute Physiological And Perceptual Responses To Body-weight Circuit And Treadmill-based High-intensity Interval Exercise In Children

Abstract

Research examining acute responses to non-laboratory-based high-intensity interval exercise (HIIE), such as body-weight exercise, in children is lacking. PURPOSE: To compare the acute physiological and perceptual responses between body-weight circuit (CIRC) and treadmill high-intensity interval running (TM) in children. METHODS: Physically active boys (n=17; age = 9.7 ± 1.3 years) completed a graded exercise test to determine maximal heart rate (HRmax), peak oxygen uptake (VO2peak) and maximal aerobic speed (MAS). Time-matched (8-min) CIRC and TM were completed in a randomized order on separate days within a 1 to 2-week period. CIRC consisted of two sets of 4 bouts of 30 s of maximal repetitions of mountain climbers, jump squats, jumping jacks, and burpees, whereas TM included 30 s bouts at 100% MAS. Both had a 30 s recovery between bouts. HR and gas exchange data were continuously assessed using a portable metabolic analyzer and HR monitor, and blood lactate concentration (BLa) was measured pre- and post-exercise. Global affect (PANAS) and exercise enjoyment (PACES) were assessed at baseline and post-exercise. Rating of perceived exertion (RPE), affect (Feeling Scale) and enjoyment (Exercise Enjoyment Scale) were recorded pre- and post-exercise and at 38% and 75% of session completion. RESULTS: Mean peak HR and VO2 were 87% HRmax and 74% VO2peak for CIRC and 89% HRmax and 80% VO2peak for TM, with a significant difference in peak VO2 between regimens (p<0.05). Yet, there were no differences in session HR, VO2 or VE (p>0.05). Post-exercise BLa was significantly higher following CIRC vs. TM (mean difference = 3.0 ± 2.2 mM, p<0.05). RPE, affect and enjoyment responses did not differ between regimens during exercise, and affect did not differ from pre- to post-exercise within or between regimens (p>0.05). Post-exercise enjoyment was significantly lower after CIRC vs. pre-exercise (mean difference = 3.9 ± 1.1, p<0.05). CONCLUSION: Although HR was similar, there was a higher peak VO2 in response to TM, paralleling previous work in adults. The greater BLa accumulation in CIRC may be explained by greater muscle recruitment required for multi-joint, dynamic movements and could explain the reduced post-exercise enjoyment. Future research should investigate higher volume protocols utilizing different body-weight exercises.