RESUMEN
BACKGROUND: Among the types of physical exercise, resistance exercises have been gaining significant attention in the COPD population. The aim of this study was to compare effects of conventional resistance training and of training by using elastic tubes on muscle strength, exercise capacity, and creatine kinase clearance in subjects with COPD. METHODS: Twenty-eight subjects with COPD were randomized into the following: resistance training with the elastic tubing group and resistance training with the weight-machine training group (conventional resistance group), performed 3 times a week for 12 weeks. The subjects were submitted to spirometry, functional exercise capacity (the 6-min walk test), muscle strength (dynamometry), and the repetition maximum test. Differences between the initial and final evaluations (Δ) and the (final - initial evaluations)/initial evaluations ×100 (Δ%) of each group were expressed as mean [95% CI]. RESULTS: Nineteen subjects (FEV1 % predicted, 52 ± 18; years, 65 ± 8) completed the training program. Similar improvements were observed in both modalities on muscle strength (knee extension, Δ%18 [6 to 29]; knee flexion, Δ%35 [17 to 54]; elbow flexion, Δ%28 [9 to 48]; shoulder abduction, Δ%41 [25 to 58] and shoulder flexion, Δ%31 [11 to 51] in the weight-machine training group (conventional resistance group); knee extension, Δ%15 [8 to 21]; knee flexion, Δ%28 [15 to 41]; elbow flexion, Δ%36 [22 to 51]; and shoulder abduction, Δ%43 [32 to 55] and shoulder flexion, Δ%43 [25 to 61] in the elastic tubing group, P < .05 for intra-group analysis and P > .05 for between groups analysis), 6-min walk test (baseline 493 ± 67m vs 12 weeks 526 ± 78 in the weight-machine training group (P = .10); baseline 493 ± 71 vs 12 weeks 524 ± 68 in the elastic tubing group (P < .01), P = .88 between groups). The elastic tubing group had lower accumulated creatine kinase levels between 24 and 72 h ((Δ%-24 [-31 to 16] than subjects in the weight-machine training group Δ%3 [-21 to 28], P = .042 between the groups. CONCLUSIONS: Training with elastic resistance provided similar changes in muscle strength and exercise capacity to conventional resistance group in the subjects with COPD. The elastic tubing group had faster creatine kinase clearance after a training session than the weight-machine training group (conventional resistance group). The ease of its application associated with similar training benefits to conventional training supported its application in clinical routine.
