Abstract
Knee extension strength measurements, such as peak torque and rate of torque development (RTD), are important characteristics relevant to muscle function. Research has shown that knee extension peak torque and RTD measurements are reliable parameters in young, college-aged adults. It is unclear if these measurements are reliable parameters in older adults. It is also unclear if these measurements are related to sit-to-stand performance. PURPOSE: The purpose of this study was to determine the reliability of knee extension peak torque and RTD measurements and their relationship with sit-to-stand performance in older women. METHODS: Twenty healthy older women (age = 67.8 ± 5.8 years) volunteered for this study. Participants reported for testing on two different occasions, separated by 2-3 days at approximately the same time of day (± 2 hours). For each testing session, participants performed a 5-repetition sit-to-stand test followed by three single-leg, isometric knee extension maximal voluntary contractions (MVCs). For the sit-to-stand test, participants stood up and sat down five times from a standard chair (43-cm seat height) as quickly as possible with their arms crossed over their chest. Sit-to-stand performance was measured by recording the time with a stopwatch from the initial seated position to the final seated position after completing five stands. For the MVCs, participants sat in an upright position and were instructed to extend the leg “as hard and fast as possible” for 3-4 seconds. Isometric peak torque and early (RTD100), late (RTD200), and maximum (peak RTD) RTD measurements were calculated and displayed by a novel strength testing device at the conclusion of each MVC and were normalized to body mass. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) were calculated between sessions to assess the reliability of knee extension peak torque and RTD measurements. The relationships between these measurements and sit-to-stand performance were determined by Pearson correlation coefficients (r). RESULTS: Knee extension peak torque, peak RTD, RTD100, and RTD200 were highly consistent between sessions, with ICCs ranging between 0.895 and 0.931 and CV values between 7.94% and 8.55%. There were significant negative correlations between sit-to-stand performance and knee extension peak torque (r = -0.490, P = 0.028), peak RTD (r = -0.534, P = 0.015), RTD100 (r = -0.535, P = 0.015), and RTD200 (r = -0.532, P = 0.016). CONCLUSION: The results of this study showed that knee extension peak torque, peak RTD, RTD100, and RTD200 were reliable measures for assessing lower-body strength in healthy, older women. These measurements were significantly correlated with sit-to-stand performance and thus, could be effective variables at predicting one’s functional ability. The predictive capacity of such variables to determine a person’s ability may be important in the early stages of rehabilitation, especially if that person is unable to perform a sit-to-stand test.
Recommended Citation
Salvador, Alfonzo G. and Palmer, Ty B.
(2025)
"Reliability and Relationships between Knee Extension Strength Measurements and Sit-to-Stand Performance in Older Women,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
17, Article 12.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss17/12