Maximal strength training of the legs in COPD: A therapy for mechanical inefficiency

HOFF, J., A. E. TJONNA, S. STEINSHAMN, M. HOYDAL, R. S. RICHARDSON, and J. HELGERUD. Maximal Strength Training of the Legs in COPD: A Therapy for Mechanical Inefficiency. Med. Sci. Sports Exerc., Vol. 39, No. 2, pp. 220-226, 2007. Purpose: A diminished mechanical efficiency (work/02 consumed) accompanies chronic obstructive pulmonary disease (COPD), and increased mechanical efficiency has been attained by maximal strength training (MST) with an emphasis on the maximal rate of force mobilization in the concentric phase in healthy subjects. This study combined these observations and evaluated the impact of short-term MST on patients with COPD. Methods: Twelve patients with COPD (FEV1 = 1.1 +/- 0.1) were pretested and then randomly assigned to either an MST group (N = 6) or a normal activity control group (N = 6). Within each MST training session (three times per week for 8 wk), patients performed four sets of seated leg presses with a focus on the rate of force development at an intensity that only allowed the performance of five repetitions. Results: Patients who performed MST significantly improved their rate of force development (105 +/- 22.8%), mechanical efficiency (32 +/- 7%), and FEV1 (21.5 +/- 6.8%), whereas these variables were unchanged in the controls. Neither group changed either peak oxygen consumption (VO2peak) or body mass. Conclusion: In combination with the observed improvement in FEV1, these data certainly support the therapeutic role for MST in the treatment of COPD.