[Relationship between functional capacity assessed by walking test and respiratory and lower limb muscle function in...

Sarcopenia is the most significant factor in the decline of peripheral and respiratory muscle strength. It can lead to progressive disability, loss of independence and impaired functional capacity.

To determine the strength of respiratory muscles (maximal inspiratory pressure - MIP and maximal expiratory pressure - MEP) and lower limb muscles, and to explore the possible relationships between these variables and the functional capacity of the elderly.

Sixty-five elderly patients (71.7+/-4.9 years old) took part in the study. Isokinetic dynamometry was used to assess the knee flexors and extensors, an analog vacuum manometer was used to assess the respiratory muscles, and the six-minute walking test was used as an outcome of functional capacity. The Mann-Whitney test and Student's t-test were used for gender comparison. The relationships were investigated using Pearson's correlation. The significance level was p<0.05.

The lower limb and respiratory muscle strength variables and the walking distance variables were higher in men than women (p<0.05). Moderate and significant correlations were found between these variables (p<0.001). The higher values were between right knee extensor average peak torque (APT) and MIP (r=0.587), left knee flexor APT and MEP (r=0.638), as well as between walking distance and left knee extensor average power (AP; r=0.614), right knee flexor AP (r=0.539), MIP (r=0.508) and MEP (r=0.541) respectively.

The relationship between walking distance and respiratory and lower limb muscle strength found in this study suggests that optimizing these functions may contribute to maintaining and improving functional capacity in the elderly.