Dominant and non-dominant side knee isokinetic characteristics of Chinese calisthenics athletes

Yu LI

ABSTRACT

BACKGROUND: A comprehensive evaluation of knee muscle strength, knee hamstrings-to-quadriceps (H/Q) force ratio, and symmetry of both knee joints is beneficial to preventing knee joint injuries. OBJECTIVE: To analyze the dominant and non-dominant side isokinetic characteristics of the knee joints of Chinese calisthenics athletes and bilateral symmetry of muscle strength. METHODS: Knee joints of 22 Chinese calisthenics athletes (aerobics group, n=8; athletics group, n=14) from Chinese national aerobics team were measured using IsoMed2000 at 60 and 180 (°)/s concentric angular speed. RESULTS AND CONCLUSION: The peak torque (PT) and the relative peak torque (PT/BW) of the flexors and extensors of the knee joint in the two groups were significantly decreased with the increase of the angular speed (P < 0.001), and the H/Q ratio significantly increased with the increase of the angular speed (P < 0.001). The dominant leg flexors strength were significantly higher than that of the non-dominant leg (P < 0.05), and extensors strength and H/Q of the dominant leg were significantly higher than those of the non-dominant leg at the speed of 60 (°)/s (P < 0.05). The H/Q of the non-dominant knee joint in the aerobic group was significantly higher than that in the athletics group at the speed of 180 (°)/s (P < 0.05). In the aerobic group, the flexor peak torque of the dominant leg was significantly higher than that of the non-dominant leg at the speed of 60 (°)/s and 180 (°)/s (P < 0.05), but there was no significant difference in both side of extensors. In the athletics group, the flexor peak torque of the dominant leg was significantly higher than that of the non-dominant leg (P < 0.05), the extensors peak torque [60 (°)/s], PT/BW [60 (°)/s] and H/Q [180 (°)/s] of the dominant leg were significantly higher than those of the non-dominant leg (P < 0.05). These findings indicate that the muscle force of the dominant and non-dominant knee joints were asymmetric, and the athletes ought to improve the muscle power of the non-dominant knee joint. A lower H/Q indicates imbalance between the flexor and extensor strength of the knee joint, and it is necessary to strengthen the knee flexor strength training, especially the training for fast strength.