Safety and possible effects of low-intensity resistance training associated with partial blood flow restriction in polymyositis and dermatomyositis

Introduction: Our aim was to evaluate the safety and efficacy of a low-intensity resistance training program combined with partial blow flow restriction (BFR training) in a cohort of patients with polymyositis (PM) and dermatomyositis (DM). Methods: In total, 13 patients with PM and DM completed a 12-week twice a week low-intensity (that is, 30% one-repetition-maximum (1RM)) resistance exercise training program combined with partial blood flow restriction (BFR). Assessments of muscle strength, physical function, quadriceps cross sectional (CSA) area, health-related quality of life, and clinical and laboratory parameters were assessed at baseline and after the intervention. Results: The BFR training program was effective in increasing the maximal dynamic strength in both the leg-press (19.6%, P < 0.001) and knee-extension exercises (25.2% P < 0.001), as well as in the timed-stands (15.1%, P < 0.001) and timed-up-and-go test (-4.5%, P = 0.002). Quadriceps CSA was also significantly increased after the intervention (4.57%, P = 0.01). Similarly, all of the components of the Short Form-36 Health Survey, the Health Assessment Questionnaire scores, and the patient-and physician reported Visual Analogue Scale were significantly improved after training (P < 0.05). Importantly, no clinical evidence or any other self-reported adverse event were found. Laboratory parameters (creatine kinase and aldolase) were also unchanged (P > 0.05) after the intervention. Conclusions: We demonstrated that a 12-week supervised low-intensity resistance training program associated with partial blood flow restriction may be safe and effective in improving muscle strength and function as well as muscle mass and health-related quality of life in patients with PM and DM.