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

Background: We examined the effects of an 8-week modified high-intensity circuit training using body weight as resistance (HICT) on health-related physical fitness in sedentary obese women.

Methods: Twenty-four sedentary obese women were allocated into the HICT or a non-training control group (CG). The modified HICT was performed for eight weeks (three times per week). Training consisted of a 30-second workout and 10-second rest for 12 exercise poses per one circuit (one circuit in the first week), with an increase of one circuit every two 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 V̇O2max), and workload.

Results: All variables were obtained at baseline, week 4, and week 8. The HICT improved FlexLH, StrengthLeg, and relative V̇O2max 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 V̇O2max, and workload (All P<0.05). Furthermore, the HICT elicited a higher change in SMM (+2.9%), BFM (-3.4%), BF% (-3.2%), MFR (+9.5%), FlexLH (+145.7%) and relative V̇O2max (+32.3%) than the CG at week-8 (All P<0.05).

Conclusions: An eight-week modified HICT program thrice a week is an effective training modality to influence health-related physical fitness in sedentary obese women.