Effects of various interval training regimes on changes in maximal oxygen uptake, body composition, and muscular strength in sedentary women with obesity

PurposeWe determined the effects of two high-intensity interval training (HIIT) regimens [the traditional (TRAD) and periodized (PER)] on changes in maximal oxygen uptake (VO(2)max), body composition, and muscular strength in sedentary, obese women.MethodsSeventeen women (age and BMI=37.510.5year and 39.14.3kg/m(2)) were randomized into a 6week regime of TRAD or PER which consisted of three sessions per week, two in the laboratory, and one on their own. Pre- and post-training, VO(2)max, body composition, and muscular strength of the knee extensors (KE) and flexors (KF) were assessed via ramp cycling to exhaustion, air displacement plethysmography, and isokinetic dynamometry, respectively.ResultsVO(2)max was increased by 4-5% in response to training (p=0.045) with no group-by-time interaction (p=0.79). Body mass, fat mass, and waist-to-hip ratio were unaltered (p>0.05) in response to training, yet there was a significant change in percent body fat (p=0.03), percent fat-free mass (p=0.03), and absolute fat-free mass (p=0.03) in TRAD but not PER. No change occurred in KE (p=0.36) or KF torque (p=0.75) in response to training and there was no group-by-time interaction (p>0.05).ConclusionsLow-volume HIIT improved VO(2)max and body composition but did not modify muscular strength, which suggests that obese women desiring to increase strength should initiate more intense HIIT or partake in formal resistance training.