Sit to Stand Muscle Power Is Related to Functional Performance at Baseline and After Supervised Exercise Training in...

Patients with peripheral artery disease (PAD) have decreased muscle power, contributing to functional limitations. The sit to stand (STS) is a validated test to assess muscle power in older individuals; however, it has never been investigated in patients with PAD. The relationship between STS muscle power, and common disease related outcomes was evaluated at baseline and following supervised exercise training (SET) in patients with PAD.

This observational study investigated patients with Fontaine stage II. Before and after SET, maximum treadmill walking distance (MWD), functional performance tests (six minute walk, STS, stair climbing, habitual gait speed), and quality of life (Short Form 36 questionnaire) were assessed. Relative (W/kg) STS muscle power was calculated using a validated equation. Multiple regressions models were used.

Ninety-five patients with PAD were included (63.1 ± 12.1 years, 67% male). Relative STS muscle power before: 2.7 W/kg, 95% confidence interval [CI] 2.5 - 2.9; after: 3.3, 95% CI 3.1 - 3.6, MWD before: 367.0 m, 95% CI 302.4 - 431.5; after: 598.4, 95% CI 515.6 - 681.3, six minute walking distance before: 418.3 metres; 95% CI 399.4 - 437.2; after: 468.8; 95% CI 452.7-484.9, stair climbing performance before: 6.8 seconds 95% CI 6.2 - 7.4); after: 5.3; 95% CI 4.9 - 5.7, habitual gait speed before: 1.10 m/s, 95% CI 1.05 - 1.14; after: 1.18, 95% CI 1.14 - 1.22 increased significantly following SET (p < .001). Similarly, physical before: 31.4, 95% CI 29.4 - 33.3; after: 35.8, 95% CI 33.9 - 37.7 and mental before: 39.5, 95% CI 37.0 - 42.0; after: 43.1, 95% CI 40.9 - 45.4 component summaries of the SF-36 also increased significantly (p < .001). Greater relative STS muscle power at baseline was significantly related to greater baseline treadmill (β < .380; p < .002) and functional (β < .597; p < .001) performance, and quality of life (β < .291; p < .050). Larger increases in relative STS muscle power following SET were associated with greater improvements in functional performance (β < .419; p < .009).

The STS test is a valid clinical tool to monitor overall functional status in patients with symptomatic PAD.