Body composition and physical fitness improve after 8 weeks of high-intensity circuit training using body weight in obese women

We examined the effects of an 8-week modified high-intensity circuit training using body weight as resistance (HICTBW) on health-related physical fitness in sedentary obese women. METHODSːTwenty-four sedentary obese women were allocated into the HICTBW or a nontraining control group (CG). The modified HICTBW was performed for 8 weeks (3 times per week). Training consisted of a 30-second workout and 10-second rest for 12 exercise poses per 1 circuit (1 circuit in the first week), with an increase of 1 circuit every 2 weeks. Body weight and body composition included skeletal muscle mass (SMM), body fat mass (BFM), body fat percentage (BF%), visceral fat area (VFA), and skeletal muscle mass to visceral fat area ratio (MFR) were measured. Physical fitness included flexibility of the lower back and hamstrings (FlexLH), and leg and handgrip muscle strength (StrengthLeg, StrengthHG). Cardiovascular endurance included the Åstrand-Rhyming heart rate (HRÅstrand), relative maximum oxygen uptake (relative V̇ O2max), and workload. RESULTSː All variables were obtained at baseline, week-4, and week-8. The HICTBW improved FlexLH, StrengthLeg, and relative V̇ O2max from baseline to week-4 (All P<0.05). Improvements from baseline to week-8 were observed for SMM, BFM, BF%, VFA and MFR, FlexLH, StrengthLeg, HRÅstrand, relative V̇ O2max, and workload (All p<0.05). Furthermore, the HICTBW elicited a higher change in SMM (+2.9%), BFM (-3.4%), BF% (-3.2%), MFR (+9.5%), FlexLH (+145.7%) and relative V̇ O2max (+32.3%) than the CG at week-8 (All P