Knee extensor/flexor muscle torque and jump performance in male volleyball players: effect of experience and torque-angle-velocity relationships

Background and objective: There are many studies that have examined the differences in isokinetic strength performance differences in athletes; however, observing these angular velocity-dependent differences on surface maps is a very practical and useful application. The aim of this study was to determine the angular velocity-dependent isokinetic knee extensor/flexor muscle strength and jump performance and to compare the test results and 3D torque-angle-velocity surface maps of amateur and professional volleyball players. Materials and methods: We included 25 well-trained male volleyball players (14 professionals and 11 amateurs) with a mean age of 21.8 ± 2.6 years (range 18–27 years) in this cross-sectional study. The dominant knee concentric muscle contractions were analyzed at 300, 120, and 60∘/s angular velocities to determine peak torque (PT), total work (TW), mean power (MP), angle of peak torque (APT), and hamstring-to-quadriceps torque ratio (H:Q). Vertical jump performance was assessed using countermovement jump (CMJ) test. These data were processed using a MATLAB algorithm for constructing the 3D torque-angle-velocity surface maps. Results and conclusions: Significant differences were identified for extensor–flexor PT between PRO and AT at 300 and 120∘/s (p < 0.05). Moreover, there were significant differences between groups for MP and APT at 300 and 120∘/s for TW at all velocities. CMJ test results were significantly different between the groups (p < 0.05). Amateur and professional male volleyball players showed different concentric knee strengths across isokinetic velocities and different eccentric strengths on CMJ test. 3D surface maps can play an important role in the comparative analysis of athletes with different sports backgrounds or in performance analyses when tracking individual development and provide a detailed and understandable perspective in revealing differences. It can also be of help in detection of possible deficits in muscle strength and load range before and after potential injuries