Association between peripheral and respiratory muscle strength and gait speed in the elderly is not mediated by peripheral muscle blood flow

Abstract

Background: The aging process affects different systems, including the musculoskeletal and respiratory systems. Both systems seem to be interconnected in relation to functional capacity deterioration in the elderly. Therefore, this study aimed to evaluate the association between peripheral and respiratory muscle strength with gait speed and its possible mediation by leg muscle blood flow (LBF) in the elderly. Methods: People aged over 65 years, of both sexes and clinically stable were evaluated. Gait speed was evaluated by the 4.6 m walking test. Maximal inspiratory pressure (MIP) and expiratory pressure (MEP) by manuvacuometry, Handgrip strength by a dynamometer (Jamar®) and LBF by venous occlusion plethysmography. Results: We included 110 patients with mean age 76.9 ± 7.2 years, 56 (50.9 %) were women, 72 (67.9 %) were classified as frail by Fried criteria and 22 (20.0 %) reported the regular practice of exercise. Baseline mean values of MIP was 59.5 ± 23.8 and MEP 68.2 ± 23.8. The median gait speed was 0.88 m/s, handgrip strength 19.5 Kg/f and LBF 2.7 ml/min/100 ml. Further analysis showed a significant association between gait speed and handgrip strength with MIP (p = 0.005, p = 0.013, respectively). However, no mediation by LBF were found. Conclusion: There is a strong association between gait speed and handgrip strength with MIP without mediation by LBF.

Keywords

• Gait speed
• Handgrip strength
• Respiratory muscle strength
• Peripheral blood flow
• Elderly