Impact of different intensities of resistance training on health status focusing on activities of daily living in patients with COPD: randomized controlled study

Abstract

Resistance training has been shown to reverse muscle dysfunction and enhance health status in patients with COPD. It is however not clear which is the optimal intensity of resistance training.

Aim: To evaluate the effect of low-load/high-repetition (LL/HR) versus high-load/low-repetition (HL/LR) resistance training intensities on dyspnea during simulated ADL tasks, exercise capacity, muscle strength and quality of life.

Methods: A randomized controlled trial was performed. Twenty-seven patients were randomized into LL/HR group (n=13, 10 male, 68.6±8.7 years, FEV1 49±16 %pred) and HL/LR group (n=14, 10 male, 69±6.8 years, FEV1 50.2±15 %pred). Patients performed chest press, high pulley, and leg press exercises. LL/HR initial load was set at 30% of 1-RM, and HL/LL was set at 60% of 1-RM. Outcomes were dyspnea during simulated ADL tasks, London Chest Activity of Daily Living Scale (LCADL), 6-minute walk distance (6MWD), shoulder flexor strength and Saint George’s Respiratory Questionnaire (SGRQ).

Results: SGRQ symptoms improved significantly more in the LL/HR group (pre= 40.2±20; post=26.4±18, p=0.002) compared to HL/LR. No difference was found for the other outcomes. Dyspnea during ADL simulation (p=0.005), LCADL physical domain (p=0.005) and total score (p=0.013), 6MWD (p=0.023), and shoulder flexor strength (p<0.001) improved significantly in both groups.

Conclusion: Our results suggest an equivalent improvement in ADL dyspnea and LCADL followed by improvements in exercise capacity and muscle strength after both LL/HR and HL/LR training. LL/HR training presented a superior effect on the SGRQ symptoms domain.