The Effect of Trunk Motion Control on Biomechanical Parameters of Knee During Landing / 医用生物力学

Objective To determine the effect of trunk motion control on knee biomechanics during single-leg landing. Methods Twenty male healthy basketball players were recruited. The kinematics, kinetics parameters and surface electromyogram (EMG) of knee joints under trunk motion control during single-leg landing were studied by using Vicon motion Analysis system, Kistler force platform and Noraxon surface EMG system. Results Compared with natural landing, there were significant differences in flexion angle at initial contact moment, peak flexion angle and peak flexion moment during deeply inspiratory landing and landing with a stick, and a significantly larger flexion angle at initial contact moment, a larger peak flexion angle and smaller peak flexion moment were also found. Compared with natural landing, there was no statistical difference in peak valgus angle and peak valgus moment, as well as EMG activity of hamstrings, quadriceps muscles of the knee during deeply inspiratory landing and landing with a stick. Conclusions Deeply inspiratory landing or landing with a stick reduce the risk of anterior cruciate ligament (ACL) injury, and the results provide the theoretical basis for prevention of ACL injuries in basketball players during landing.

Dominant and non-dominant side knee isokinetic characteristics of Chinese calisthenics athletes / 中国组织工程研究

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.

Effect of lower-limb dominance and non-dominance shuttle runs under load carriage on the balance responses in young cadets / 中国应用生理学杂志

OBJECTIVE@#This test was designed to evaluate the effect of lower-limb dominance and non-dominance shuttle runs under load carriage during different exercise load at the same exercise intensity on the balance responses.@*METHODS@#Ten healthy young males were joined in this experiment, they were (20.80±2.04) years old and (173.99±2.87) cm tall. In a randomized cross-over design, they performed four times shuttle runs under unilateral load carriage:20 m×5 at dominant side, 20 m×5 at non-dominant side, 20 m×10 at dominant side, 20 m×10 at non-dominant side respectively. Balance abilities were evaluated immediately and 20 minute post-exercise respectively, and R-R interval was recorded.@*RESULTS@#The HR, EPOC and TRIMP for all exercise load were increased significantly after shuttle runs compared to rest (0.05), which showed symmetrical change. In addition, during 20 minute recovery, the balance ability for all exercise load was returned to the rest value (>0.05).@*CONCLUSIONS@#The shuttle runs could impair the trunk control ability immediately post-exercise, the magnitude of mediolateral movement was increased as the exercise load increased. The changes of balance responses were similar between the dominant and the non-dominant side, the dominant and the non-dominant side might show cross-effects.

Comparison of NCV of Right and Left Limb in Right handed Male Subjects.

Background: Nerve Conduction Velocity is affected by various factors like age gender & temperature. Various studies have been done regarding development of brain and dominance of right or left side, some studies have found differences between left and right hand for nerve conduction. Our aim is to compare NCV of dominant limb to nondominant limb in right hand dominant subjects and to find out if different normal values should be considered in right and left hand. Methods: The Median and Common Peroneal Nerve (CPN) of dominant as well as Non- dominant limb were used for measuring Motor & Sensory Nerve Conduction Velocity (MNCV & SNCV) in age groups of 31-35 and 36- 40 years using Medicaid system. Results: We found p value was insignificant using unpaired t-test for MNCV & SNCV of Median and Common Peroneal Nerve of left and right side. Similarly, the MNCV & SNCV of dominant and nondominant limb for median and CPN were insignificant. Conclusion: Consideration of right or left side dominance is not necessary while measuring NCV in asymptomatic subjects and different set of normal values are not required for right and left hand.