Measuring Quadriceps Muscle Strength

The Biodex™ (Shirley, NY, United States) isokinetic dynamometer system (Biodex System 3 Pro) was used to measure the muscle strength of the knee extensor muscle (quadriceps femoris). This device is reliable and accurate for measuring muscle strength (Drouin Joshua et al., 2004 (link)). Participants sat with their hands folded in front of their chests, hips flexed to 90°, and waists restrained with system-equipped straps. The axis of rotation of the knee joint was kept aligned with the axis of rotation of the isokinetic dynamometer system by placing an immobilization pad over the ankle joint. The measured angular velocity was set to 60°/s (Chang et al., 2019 (link)). Each participant took two pretest values before the start of muscle strength measurements. At the beginning of the analysis, the participants were directed to repeat the flexion and extension of the knee joint five times continuously at a speed of 60°/s, using their maximum muscle strength. Muscle strength was represented by normalized mean peak torque (Nm) divided by body weight (Kg), with higher values indicating greater muscle strength. The entire measurement process was conducted in a standardized manner for all participants under the same directions and encouragement. The results were collected in a duplicate manner and presented as mean values.