Effects of increasing isokinetic angular velocity on concentric and eccentric strength

There is an inverse relationship between the ability to generate force during concentric muscle movements and the velocity of contraction. However, this relationship is not the same in eccentric muscle movements due to differences in mechanism. Therefore, the study aimed to investigate the effects of higher isokinetic angular velocity on concentric and eccentric strength in the hamstring and quadriceps muscles. Twenty-four students from the faculty of sports science, aged between 18 and 24, participated in the study voluntarily. The participants completed a 5-minute standard warm-up, followed by concentric and eccentric knee extension (quadriceps) and knee flexion (hamstring) movements in the dominant leg at slower (60◦ /s) and faster (180◦ /s) angular velocities on the Cybex device (Cybex NORM®, Humac, CA, USA, 2004). The isokinetic strength outputs at slower and faster angular velocities were compared a one-way repeated-measures analysis of variance. When comparing the forces involved in concentric knee extension and flexion at slower and faster angular velocities, it was found that the force decreased significantly at higher speeds both during extension and flexion (p < 0.001). However, there was no significant changes in eccentric knee extension and flexion force outputs between slower and faster angular velocities (p > 0.05). Eccentric force outputs were significantly higher than concentric force in both angular velocities (p < 0.001). These results show that there is an inverse relationship between the velocity of concentric contractions and strength outputs, but not in eccentric contractions. It emphasizes the importance of healthcare professionals considering suitable exercise methods for athletes, especially when it comes to improving muscle strength or aiding in rehabilitation processes.