Aerobic high-intensity interval training and maximal strength training in patients with unspecific musculoskeletal disorders improve VO2peak and maximal strength more than moderate training

Improving peak oxygen uptake (VO2peak) and maximal strength are key objectives of rehabilitation for patients with unspecific musculoskeletal disorders (MSDs). Although high-intensity training yield superior outcomes for these factors, patients with MSDs may not tolerate high-intensity due to pain and fear. Therefore, we examined the effect and feasibility of incorporating aerobic high-intensity intervals (HIITs) and maximal strength training (MST) in a standard clinical rehabilitation program for patients with unspecific MSDs. 73 patients (45 +/- 10 years) with MSDs partaking in a standard, public, and 4-week rehabilitation program were randomized to high-intensity training (HG: 4 x 4 minutes intervals at similar to 90% of maximal heart rate; HRmax, and 4 x 4 repetitions leg press at similar to 90% of 1 repetition maximum; 1RM, with maximal intended velocity) or keep todays treatment of low-to moderate-intensity training (MG: various cycling, walking, and/or running activities at similar to 70%-80% of HRmax and 3 x 8 - 10 repetitions leg press at similar to 75% of 1RM without maximal intended velocity). HG improved VO2peak (12 +/- 7%) and leg press 1RM (43 +/- 34%) more than moderate-intensity group (VO2peak; 5 +/- 6%, 1RM; 19 +/- 18%, both p < 0.001). We observed that no adverse events and no between-group differences in dropout rate or self-reported quality of life (both p > 0.05). There were positive correlations between improved VO2peak and improved physical (p = 0.024) and emotional (0.016) role functioning. We conclude that both high-intensity interval training and MST are feasible and improve VO2peak and maximal strength more than standard low-to moderate-intensity treatment of patients with unspecific MSDs. Our findings suggest that high-intensity training should be implemented as a part of standard clinical care of this patient population.