Effects of Isokinetic Flexion and Extension Training at Different Angular Velocities on Core Muscles of Patients with Low Back Pain / 中国康复理论与实践

Objective:To explore the effect of isokinetic muscle strength training at different angular velocities on the core muscles of patients with low back pain, and to find out the better angular velocity. Methods:From January, 2016 to June, 2018, 60 patients with chronic low back pain were randomly divided into three groups, with 20 cases in each group. Group A (control group) only received routine rehabilitation therapy. Additionally, groups B and C received isokinetic muscle strength training at 30°/s and 90°/s, respectively, three times a week for four weeks. They were measured peak torque and average power before and after training. Results:After training, the peak torques and powers of both flexor and extensor were higher in groups B and C than in group A (P < 0.05), the peak torques of both flexor and extensor were lower in group C than in group B (P < 0.05), however, no significant difference was found in powers of both flexor and extensor between groups B and C (P > 0.05). After training, the score of VAS decreased in groups B and C (t > 4.098, P < 0.01), and was lower in groups B and C than in group A (P < 0.05), however, no significant difference was found between groups B and C (P > 0.05). Conclusion:Isokinetic muscle strength training could increase the peak torque and power of trunk flexor and extensor in patients with low back pain, in which lower angular velocity (30°/s) has a better effect.

Golf Swing Rotational Velocity: The Essential Follow-Through

OBJECTIVE: To evaluate if shoulder and pelvic angular velocities differ at impact or peak magnitude between professional and amateur golfers. Golf swing rotational biomechanics are a key determinant of power generation, driving distance, and injury prevention. We hypothesize that shoulder and pelvic angular velocities would be highly consistent in professionals. METHODS: Rotational velocities of the upper-torso and pelvis throughout the golf swing and in relation to phases of the golf swing were examined in 11 professionals and compared to 5 amateurs using three-dimensional motion analysis. RESULTS: Peak rotational velocities of professionals were highly consistent, demonstrating low variability (coefficient of variation [COV]), particularly upper-torso rotational velocity (COV=0.086) and pelvic rotational velocity (COV=0.079) during down swing. Peak upper-torso rotational velocity and peak X-prime, the relative rotational velocity of uppertorso versus pelvis, occurred after impact in follow-through, were reduced in amateurs compared to professionals (p=0.005 and p=0.005, respectively) and differentiated professionals from most (4/5) amateurs. In contrast, peak pelvic rotational velocity occurred in down swing. Pelvic velocity at impact was reduced in amateurs compared to professionals (p=0.019) and differentiated professionals from most (4/5) amateurs. CONCLUSION: Golf swing rotational velocity of professionals was consistent in pattern and magnitude, offering benchmarks for amateurs. Understanding golf swing rotational biomechanics can guide swing modifications to help optimize performance and prevent injury.

THE EFFECTS OF VARIOUS ANGULAR VELOCITIES ON KNEE KINESTHESIA / 体力科学

In this study, we investigated whether a difference in the angular velocity has an effect on proprioceptive sensibility in 30 healthy subjects. Knee detection of passive motion at five angular velocities (0.1°/s, 0.2°/s, 0.3°/s, 0.4°/s, and 0.5°/s) was carried out from a starting position of 15° knee flexion for extension using a proprioception testing device. At 0.1°/s, the elapsed time was longer than that of the other angular velocities and the angular displacement was bigger as well. There were no significant differences among the remaining angular velocities (0.2～0.5°/s). Therefore it is suggested that a healthy knee has less proprioception at an angular velocity of 0.1°/s.

Interlimb Interaction at Different Angular Velocity in Isokinetic Knee Evaluation

OBJECTIVE: To investigate the influence of angular velocity on the interlimb interaction induced by movement patterns. METHOD: Sixty healthy adult men performed five maximal isokinetic knee extension-flexion contractions in each of two contralateral leg stabilization conditions at different angular velocities. In the "Front condition", the test was done with a bar in front of the ankle joint of the non-testing leg. In the Fix condition", the non-testing leg was strapped and induced reciprocally to perform isometric contractions with respect to the testing leg. From the measured values, we calculated the strength difference ratio ([Peak Torque (PT) of "Fix condition"-PT of "Front condition"x100/PT of "Front condition") at each angular velocity. RESULT: By comparing the extensor strength, greater PTs were measured at the "Fix condition" in all tested angular velocities (p<0.01). For the flexor, the PTs of both conditions were similar. The strength difference ratio decreased as angular velocity increased (r=-0.48, p<0.01) in the extensor. CONCLUSION: We could infer the crossed extension-flexion reflex is more apparent in the lower angular velocity than in higher one.

The angular displacement and angular velocity of the upper limb during elbow extension activities in spinal cord injury patients and normal individuals / 中华物理医学与康复杂志

Objective To study upper limb motor strategies during elbow extension activities in C5-6 spinal cord injury (SCI) patients and compare them with the strategies of normal individuals. Methods A Peak Motus motion analysis system was used to measure the angular displacement and the angular velocity of the shoulder, elbow and wrist of fifteen C5-6 SCI patients and fifteen healthy subjects during four elbow extension activities including grasping a cup, reaching for a light switch, wheelchair ambulation and upper limb weight-bearing. Results Compared with normal individuals, the movement time of the SCI patients was significantly longer during the grasping, reaching and wheelchair ambulation activities. The angular velocity was significantly slower during reaching for a light switch and wheelchair ambulation. The patients with spinal cord injury performed the motor tasks primarily relying on increasing or decreasing the angular displacement of the shoulder during the former three elbow extension activities. They compensated for any functional deficiency by changing the movement direction of the shoulder and elbow in sagittal projection during upper limb weight-bearing activities. Conclusion C5-6 SCI patients utilize different motor patterns and strategies from healthy subjects to complete elbow extension activities.

Mechanical properties of dynamic muscle contraction against viscosity resistance(isoviscous contraction). Its comparison with isotonic and isokinetic contraction / 体力科学

The present study attempted to define a dynamic muscle contraction against viscosity resistance in which force is proportional to velocity of movement, and to determine its mechanical properties in comparison with isotonic and isokinetic muscle contraction. This dynamic contraction was referred to as the “isoviscous contraction” . A loading mechanism consisting of a directly-driven electromagnetic motor and an electronic control circuit was developed to enable three patterns of dynamic contraction to be performed. The torque, joint angle and joint angular velocity in the three types of dynamic contraction were measured in 8 healthy male volunteers during knee joint extension. The isoviscous contraction was not accompanied by any abrupt change in torque during the movement observed regularly in isotonic and isokinetic contraction. The instructed movement for isoviscous contraction could be performed over a wide range of joint motion at all levels of contraction. In addition to its unique mechanical properties, since the viscosity resistance produces a better damping effect against an abrupt change in torque, isoviscous contraction is considered to be a useful method of rehabilitation training in disabled patients and aged individuals. However, the great inertial force produced by isoviscous contraction corresponding to that in isotonic contraction should be further investigated.

Electromyogram patterns during ankle joint movements at various angular velocities in the triceps surae muscles / 体力科学

Surface electromyograms (EMGs) were recorded from the triceps surae muscles in order to examine muscle activities during concentric and eccentric ankle joint movements at various angular velocities under constant load (5 and 10%MVC) . The results were summarized as follows ;<BR>1) At slow angular velocity (6 deg/s) of ankle joint movement, EMG amplitude tended to increase at a larger ankle joint angle in the gastrocnemius muscle, and at a smaller angle in the soleus muscle.<BR>2) Following an increase in angular velocities (6→30→60 deg/s), peak values of integrated EMGs were significantly increased (7-15%) in the medial gastrocnemius muscle. However, these peak values were significantly decreased in the soleus muscle (22-49%) . These results suggest selective recruitment of motor units depending on angular velocity.<BR>3) Ankle joint angle at the peak integrated EMGs was significantly increased following an increase in angular velocity (6→30→60 deg/s) in the soleus muscle. This suggests that the angle at the recruitment of motor units may be dependent on angular velocity in the soleus muscle.