In-situ neutron diffraction has been employed to examine the effect of strain path on lattice strain evolution during monotonic and cyclic tension in an extruded Mg-8.5wt.%Al alloy. In the cyclic tension test, the maximum applied stress increased with cycle number. Lattice strain data were acquired for three grain orientations, characterized by the plane normal to the stress axis. The lattice strain in the hard {10.0} orientation, which is unfavorably oriented for both basal slip and {10.2} extension twinning, evolved linearly throughout both tests during loading and unloading. The {00.2} orientation exhibited significant relaxation associated with {10.2} extension twinning. Coupled with a linear lattice strain unloading behavior, this relaxation led to increasingly compressive residual strains in the {00.2} orientation with increasing cycle number. The {10.1} orientation is favorably oriented for basal slip, and thus showed a soft grain behavior. Microyielding occurred in the monotonic tension test and in all cycles of the cyclic test at an applied stress of ~50 MPa, indicating that strain hardening in this orientation was not completely stable from one cycle to the next. The lattice strain unloading behavior was linear in the {10.1} orientation, leading to a compressive residual strain after every cycle, which, however, did not increase systematically from one cycle to the next as in the {00.2} orientation.
This study aimed to examine the most effective exercise method for shoulder joint rehabilitation by comparatively observing activity of shoulder stabilizer muscles during push up and push up plus exercises under diverse stable conditions. The subjects were 20 healthy adults students who went to M university. While the subjects conducted push up and push up plus exercises under diverse stable conditions(a stable surface, a support of 25cm height, a support of 30 cm height and a balance pad), activities of the upper trapezius muscle, pectoralis major muscle, serratus anterior muscle, and triceps brachii muscle were recorded. During push up and push up plus exercises, activities of the stabilizer muscles were higher when the stable condition was changed rather than on the stable surface. In particular, when the support of 30cm height and balance pads were applied, activity of the shoulder stabilizer was highest. There were significant differences in the upper trapezius muscle and triceps brachii muscle during the push up exercise(p<.05) and in the serratus anterior muscle during the push up plus exercise(p<.05). Activities of the shoulder stabilizers were higher when the upper and lower limbs' surface stable conditions were changed than the stable surface. Therefore, when programs for rehabilitation of shoulder joints are applied, provision of diverse stable conditions according to patients' conditions will be effective methods.
This study is intended to examine the motor skill learning and treadmill exercise on motor performance and synaptic plasticity in the cerebellar injured rats by harmaline. Experiment groups were divided into four groups and assigned 15 rats to each group. GroupⅠ was a normal control group(induced by saline); GroupⅡ was a experimental control group(cerebellar injured by harmaline); GroupⅢ was a group of motor skill learning after cerebellar injured by harmaline; GroupⅣ was a group of treadmill exercise after cerebellar injured by harmaline. In motor performance test, the outcome of groupⅡ was significantly lower than the groupⅢ, Ⅳ(especially groupⅢ)(p<.001). In histological finding, the experimental groups were destroy of dendrities and nucleus of cerebellar neurons. GroupⅢ, Ⅳ were decreased in degeneration of cerebellar neurons(especially groupⅢ). In immunohistochemistric response of synaptophysin in cerebellar cortex, experimental groups were decreased than groupⅠ. GroupⅢ's expression of synaptophysin was more increased than groupⅡ, Ⅳ. In electron microscopy finding, the experimental groups were degenerated of Purkinje cell. These result suggest that improved motor performance by motor skill learning after harmaline induced is associated with dynamically altered expression of synaptophysin in cerebellar cortex and that is related with synaptic plasticity.
The purpose of this study was to investigate the distribution of trig˗ ger points(TrPs) on athletes with various sporting background. To achieve the purpose, a study was carried out through a survey from 180 athletes involved in 6 selected sports at Yong-In University. Selected sports included Judo, Taekwondo, Kendo, Ssi-reum(Korean traditional wrestling), Boxing, and Golf. An interview type survey and physical examination were conducted with each thirty athletes from each of the selected sports groups. Technical statistic(SPSS 15.0) was used to analyze the distribution of TrPs on these athletes. The most common TrPs observed in muscles of Trapezius, Quadratus Lumborum, Quadriceps in Judo. In Taekwondo, it was on the trapez˗ ius and triceps surae. Kendo athletes had TrPs at sites of trapezius, brachioradialis and triceps surae. Ssirem athletes were found to have TrPs on trapezius, deltoid and quadrates lumborum. In boxers, TrPs appearing at trapezius and brachioradialis were observed. Finally, Golf players were seen to have TrPs at trapezius, quadrates lumbo˗ rum and brachioradialis. Hence, the analysis shows that there are significant differences of the distribution of TrPs according to the different sport items of the athlete.