Resumen

SPRUIT, Martijn A. et al. Age-graded reductions in quadriceps muscle strength and peak aerobic capacity in COPD. Rev. bras. fisioter. [online]. 2012, vol.16, n.2, pp. 148-156.  Epub 01-Mar-2012. ISSN 1413-3555.  http://dx.doi.org/10.1590/S1413-35552012005000011.

BACKGROUND: Reductions in quadriceps strength and peak aerobic capacity (VO₂) in patients with chronic obstructive pulmonary disease (COPD) have been studied in relatively small samples over a short period. Moreover, results were not corrected for confounding variables, such as lean muscle mass, gender, and gas transfer capacity of the lungs. OBJECTIVES: To compare quadriceps muscle strength and peak V^.O₂ in women and men while stratifying for age and gas transfer capacity. We then corrected for lower-limb lean muscle mass to see whether and to what extent the age-graded reduction remained evident. METHODS: Retrospectively, data of 374 women and 593 men with COPD were analyzed: lung function, current drug therapy, quadriceps strength, peak V^.O₂, lower-limb lean muscle mass, and gas transfer capacity. RESULTS: Quadriceps strength and peak V^.O₂ were lower in older women and men with a gas transfer capacity of <50% predicted, also after adjustment for lower-limb lean muscle mass. Moreover, quadriceps strength and peak V^.O₂ were lower in older women and men with a gas transfer capacity of <50% predicted, also after adjustment for lower-limb lean muscle mass. Moreover, quadriceps strength and peak V^.O₂ were related to age in COPD, particularly in women and men with a gas transfer capacity of >50% predicted. Yet, counter to our hypothesis, lower-limb lean muscle mass did not show an age-graded reduction and, in turn, could not account for the relationship of age with quadriceps strength and peak V^.O₂. CONCLUSIONS: It is apparent that there is an age-graded reduction in skeletal muscle function in patients with COPD. Therefore, prevention of an age-graded decline in quadriceps muscle strength and peak V^.O₂ may need to become an outcome of pulmonary rehabilitation of patients with COPD.

Palabras llave : Chronic obstructive pulmonary disease; lower-limb lean muscle mass; peak aerobic capacity; quadriceps muscle strength; isokinetic quadriceps peak torque; aging.