Hybrid-type, multicomponent interval training upregulates musculoskeletal fitness of adults with overweight and obesity in a volume-dependent manner: A 1-year dose-response randomised controlled trial

This study examined the dose-response effects of a 1-year hybrid-type, multicomponent interval training programme (DoIT) on various musculoskeletal fitness parameters in inactive overweight and obese adults in a gym setting. Ninety-seven middle-aged (44.8 +/- 5.2 years) individuals with overweight/obesity (31.2 +/- 5.7 kg/m(2)) (66% female) were randomly assigned to the following groups: (i) no-intervention control (CON, n = 29), (ii) DoIT performed once weekly (DoIT-1, n = 24), (iii) DoIT performed twice weekly (DoIT-2, n = 23) and (iv) DoIT performed thrice weekly (DoIT-3, n = 21). DoIT was a time-efficient, intermittent-based, multicomponent exercise protocol using progressive loaded fundamental movement patterns with prescribed work-to-rest intervals (1:3-2:1) in a circuit format (2-3 rounds). Muscular strength, muscular endurance, flexibility, passive range of motion (PRoM), static balance and functional movement screen (FMS (R)) were assessed at baseline, 6 and 12 months following intervention. At post-training, all exercise groups exhibited superior changes than CON in (i) muscular strength (+13%-38%, p < 0.001); (ii) muscular endurance (+42%-159%, p < 0.001); (iii) flexibility (+12%-42%, p< 0.001); (iv) PRoM (+6%-50%, p = 0.001-0.026); (v) static balance (+61%-163%, p < 0.001); and (vi) FMS (+18%-39%, p < 0.001). Although a single exercise session/week improved musculoskeletal fitness, changes demonstrated a step-wise improvement with two and three sessions/week suggesting a dose-dependent response. The response rate to training was 100% for all exercise groups. These findings suggest that a multicomponent exercise approach incorporating bodyweight drills and resistance-based alternative modes performed under real-world conditions may improve several musculoskeletal fitness indicators in a dose-dependent manner in inactive, middle-aged adults with overweight/obesity.