The reliability of the strength knee extensor muscle using a knee muscle force measurement device

The purpose of the present study was to examine the reliability of an isometric knee muscle force measurement device.
Thirty-four healthy non-athlete subjects (17 males and 17 females, aged between 19-25) participated in the study. The maximal isometric muscle strength of the knee extensor muscles were measured at different times and on different days using a newly designed knee muscle force measurement apparatus. On each occasion, participants performed three maximum voluntary contractions in each direction of knee extension movement. The interclass correlation coefficient (ICC) and standard deviation within subjects (Sw) were computed to evaluate the reliability and magnitude of measurement error between measurements.
The results of the intra-rater, test-retest, and inter-rater reliabilities (ICCs ≥0.90, Sws ≤ 9.1 N) indicate that the knee muscle force measurements were highly repeatable and varied slightly between measurements. There were no statistically significant difference in knee muscle force measurements between times, days, and raters. Maximal isometric muscle strengths were significantly higher in males compared with that in females (p The isometric muscle force measurement device used in the present study appears to be a reliable and useful instrument for measuring the force of the knee extensors. It could also be suitable for the assessment of a physiotherapeutic or rehabilitation program.