Introduction

Patients with COPD often struggle tolerating the high-load strength training (HL-ST) required for muscle adaptations during pulmonary rehabilitation (PR). Low-load blood-flow restriction strength training (LL-BFR-ST) allows substantial reductions in training load for equal gains in muscle mass and strength.

Aim

We aimed to investigate the effects of LL-BFR-ST vs HL-ST on leg muscle strength in patients with stable COPD.

Methods

COPD patients participating in outpatient PR (24 sessions, 2x/week) were randomly assigned to lower limb LL-BFR-ST (70% occlusion pressure, 30% 1-repetition maximum) or HL-ST (70% 1-repetition maximum). Primary outcome was isometric leg strength. We secondarily investigated dynamic strength, functional capacity, physical activity, health-related quality-of-life, adverse events, perceived exertion and subjective feedback.

Results

We recruited 30 patients (63 [59,68] years, FEV1 49 [35,67]% pred.), 6 did not complete the study. No adverse events associated with the intervention occured. Isometric strength of knee extensor (data are pre-post median [quartiles] changes for HL-ST and LL-BFR-ST groups; right leg: 8.9 [-1.3,35.5] and 8.4 [-2.0,16.6] Nm; left leg: 8.3 [-0.6,20.4] and 8.6 [5.6,11.8] Nm) and flexor (right leg: 6.3 [-3.9,13.9] and 8.7 [-3.8,12.8] Nm; left leg: 2.4[-3.7,9.6] and 11.8[-7.6,16.4] Nm) muscles improved in both groups with no clinically and statistically relevant between-group differences.Physical activity improved only in the LL-BFR-ST group (165[-645,1414] and 1854[1564,2805] steps/day).

Conclusions

Similar strength gains were achieved in the LL-BFR-ST and the HL-ST group with LL-BFR-ST eliciting less exercise-induced dyspnoea.