Related Experiment Video
Updated: May 29, 2026
Lower Limb Biomechanical Analysis of Healthy Participants
Published on: April 15, 2020
Test-retest reliability of the Biodex System 4 Isokinetic Dynamometer for knee strength assessment in paediatric
Margarita D Tsiros1, Paul N Grimshaw, Anthony J Schield
1Nutritional Physiology Research Centre, School of Health Sciences, University of South Australia, Adelaide, SA, Australia.
Background:
Isokinetic dynamometry is a widely used tool for measuring muscle strength in clinical intervention and rehabilitation as well as research in children.
Objective:
To assess the test-retest reliability of knee flexor/extensor strength using the Biodex Multi-Joint System 4 Isokinetic Dynamometer in children.
Methods:
Peak isometric knee extensor (KE) and peak isokinetic knee flexor (KF) torques of the dominant and nondominant limbs were assessed twice in 11 children aged 10 to 13 yrs, 7 to 10 days apart.
Results:
Peak torques were higher in the dominant limb (p ≤ 0.006). Peak isometric KE torque was 8.4% higher (SEM 2.5%) at the second testing session, but there was no interaction with the limb tested (p > 0.2). Peak isokinetic KE/KF torque ratios agreed well between tests and had intraclass correlation coefficients (ICCs) of 0.96.
Conclusions:
The dynamometer provides a reliable means of assessing knee strength in 10 to 13 year olds, with excellent test-retest reliability for isokinetic KE/KF. A learning effect occurred when assessing isometric torque, indicating the importance of habituation for this measure.
