Upper limb muscle strength & endurance in chronic obstructive pulmonary disease

BACKGROUND & OBJECTIVES There are very few studies that have investigated the muscle strength and endurance of upper limbs (UL) in chronic obstructive pulmonary disease (COPD). We undertook this study to measure and compare the skeletal muscle strength and endurance of UL in COPD patients and age matched healthy controls and to study the association between lung function parameters and UL muscle strength and endurance. METHODS Forty one COPD patients and 45 height and weight matched healthy subjects of the same age group were studied. UL skeletal muscle strength and endurance were measured using the hand grip dynamometer test. Forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV₁), forced expiratory flow during 25-75% FVC (FEF (25-75%)) and peak expiratory flow rate (PEFR) were measured. The handgrip muscle strength and endurance between the two groups were compared and correlations between FVC and FEV 1 with muscle strength and endurance were analyzed. RESULTS The mean handgrip strength and mean muscle endurance in COPD patients were significantly lesser than the normal subjects in both males and females (P<0.001). There was significant positive correlation between muscle strength and FVC in males (r² =0.32, P<0.05); and between muscle strength and FEV₁ in females (r² =0.20, P<0.05). INTERPRETATION & CONCLUSION The study showed that the handgrip muscle strength decreases as the FVC and FEV₁ decrease in patients with COPD. Identifying those patients who have reduced strength and endurance will allow early interventions targeted at improving the quality of life of the patient.