Association Between Protocols of the Sit-to-Stand Test and Lower Limb Muscle Force Output in Patients on Hemodialysis and Subjects Without Chronic Kidney Disease

Objective: To evaluate the association of three protocols of the sit-to-stand (STS) test with muscle force output of knee extension (KE) and knee flexion (KF) in patients on hemodialysis and subjects without chronic kidney disease. Methods: This cross-sectional study included a hemodialysis group [n = 60, 59.5 (16.8) years, 55% female] and a control group [n = 60, 43.0 (11.8) years, 50% female]. The assessments were performed in 2 days, and the participants were submitted to three pro-tocols of STS test (5-repetition STS, 10-repetition STS and 30-s STS) or muscle force output of the KE and KF evaluation by handheld dynamometer based on randomization. Results: The hemodialysis group presented reduced muscle force output of the KE and KF, a longer time to perform the 5 STS and 10 STS tests, and a lower number of repetitions in the 30-s STS test. The three STS tests were associated with muscle force output of the KE in the hemodialysis group, in which the 10-repetition STS test showed the best association (R2 = 0.47; adjusted R2 = 0.42). However, the only association between the STS test and muscle force output of the KE in the control group was found in the 10-repetition STS test (R2 = 0.20; adjusted R2 = 0.13). Conclusions: The three protocols of STS tests were associated with muscle force output of the KE in patients on hemodialysis. However, the 10-repetition STS test was the best protocol to estimate the quadriceps muscle torque in these patients.

Automated summary

The study aimed to evaluate the association between sit-to-stand (STS) protocols and muscle force output of knee extension and knee flexion in hemodialysis patients and control subjects. The results showed that the hemodialysis group had reduced muscle force output for knee extension and flexion, longer time to perform the STS tests, and fewer repetitions in the 30-second STS test. All three STS tests were associated with knee extension muscle force output in the hemodialysis group, with the 10-repetition STS test showing the strongest association. However, in the control group, only the 10-repetition STS test was associated with knee extension muscle force output.