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

ABSTRACT

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 (∆CAT: LL/HR = −3.9; HL/LR = −2.8) and exercise capacity (∆ tolerance time in CWRT: LL/HR = +450.9s; HL/LR = +583.4s) above minimal clinically important difference value. Nevertheless, improvement in quality of life (∆SGRQ: LL/HR = −3.8; HL/LR = −10) and in isometric muscle strength (∆KExt: LL/HR = +15.8 N; HL/LR = +37.7 N and (∆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.

KEYWORDS:

• Chronic obstructive pulmonary disease
• quality of life
• exercise
• muscle strength

Acknowledgments

The authors thank the university where this study was developed, the financing by funding agencies and the colleagues of Spirometry and Respiratory Physiotherapy Laboratory. Besides, the authors make sincere acknowledgments for the contribution of Blinded who provided research assistance for this article.

Declaration of Interest

The authors declare no conflict of interest.