Effects of low and high resistance training intensities on clinical outcomes in patients with COPD-a randomized trial

Aim To compare the effects of two different intensities of combined resistance and aerobic training on physical-functional aspects and perceptual aspects of health status in patients with Chronic Obstructive Pulmonary Disease (COPD). Design This was a randomized parallel group trial. Methods Thirty-one patients were assessed regarding: symptoms (COPD Assessment Test - CAT), quality of life (Saint George's Respiratory Questionnaire - SGRQ); exercise capacity (six-minute walk test and constant-workload resistance test - CWRT); and muscle strength (one-repetition maximum test and isometric muscle strength for knee extensors - Kext and elbow flexors - EFlex). Patients were randomized in two groups to perform a combined training: 1) LL/HR = Low-load/high-repetition resistance training (n = 16; 68 +/- 9.3 years; FEV1 = 50.0 +/- 15.7%pred); and 2) HL/LR = High-load/low-repetition resistance training (n = 15; 70 +/- 6.5 years; FEV1 = 46.8 +/- 14.5%pred), and underwent 36 sessions. Results Symptoms, quality of life and exercise capacity presented significant improvement (p < .05) in both groups. Both intensities of resistance training improved symptoms ( increment CAT: LL/HR = -3.9; HL/LR = -2.8) and exercise capacity ( increment tolerance time in CWRT: LL/HR = +450.9s; HL/LR = +583.4s) above minimal clinically important difference value. Nevertheless, improvement in quality of life ( increment SGRQ: LL/HR = -3.8; HL/LR = -10) and in isometric muscle strength ( increment KExt: LL/HR = +15.8 N; HL/LR = +37.7 N and ( increment EFlex: LL/HR = +9.5 N; HL/LR = +29.9 N) was observed only in the HL/LR group, which also presented a larger number of responders considering isometric muscle strength. Conclusion High-intensity resistance training in a combined training was more effective in ameliorating several aspects of patients with COPD, responding more and better to physical-functional aspects and perceptual aspects of health status.