Background: High-intensity interval training (HIIT) performed on exercise cycle or treadmill is considered safe and often more beneficial for fat loss and cardiometabolic health than moderate-intensity continuous training (MICT). The aim of this pilot study was to assess the feasibility and effectiveness of a 12-week boxing training (HIIT) intervention compared with an equivalent dose of brisk walking (MICT) in obese adults.
Methods: Men and women with abdominal obesity and body mass index >25 kg/m(2) were randomized to either a boxing group or a brisk walking (control) group for 12 weeks. Each group engaged in 4 training sessions per week, equated for total physical activity. Feasibility outcomes included recruitment rates, assessment of training intensities, adherence and adverse events. Effectiveness was assessed pre and post intervention via pertinent obesity-, cardiovascular-, and health-related quality of life (HRQoL) outcomes.
Results: Nineteen individuals expressed an interest and 63% (n = 12) consented. Recruitment was slower than anticipated (1.3 participants/week). The boxing group trained at a significantly higher intensity each week versus the brisk walking group (p < 0.05). Two participants in the boxing group experienced an adverse event; both continued to exercise with modifications to the exercise program. No other adverse events were noted. The boxing group attended more sessions (79% vs. 55%) and had a lower attrition rate (n = 0 vs. n = 2) than the walking group. Analysis of covariance revealed that the boxing group significantly improved body fat percentage (p = 0.047), systolic blood pressure (p = 0.026), augmentation index (AIx; p < 0.001), absolute VO2max (p = 0.015), and Physical Functioning (p = 0.042) and Vitality (p = 0.024) domains of HRQoL over time. The walking group did not improve any clinical outcomes, and experienced a worsening of Vitality (p = 0.043).
Conclusions: Boxing training (HIIT) in adults with abdominal obesity is feasible and may elicit a better therapeutic effect on obesity, cardiovascular, and HRQoL outcomes than an equivalent dose of brisk walking (MICT). Robustly designed randomized controlled trials are required to confirm these findings and inform clinical guidelines and practice for obesity treatment.
Trial registration: ACTRN12615000007538.
Keywords: Body composition; Exercise; Fat loss; Health; High-intensity interval training; Quality of life; Weight loss.