Purpose : The purpose of the present study was to investigate the effects of ballistic stretching techniques on the flexibility, muscle strength and electrophysiologic nature. Methods : The subjects of the study were 20 young adults including 10 for the ballistic-stretching group, and 10 for the control group. This study measured hamstring flexibility, muscle strength, median frequency and root mean square on electromyography signals. All measurements were analyzed using independent sample t-tests. Results : VAS, FPRS, and ODI showed significant pain decrease in all groups except for the ODI measurement in the 0.5㎐ group. There were no significant differences according to frequency levels. Conclusion : It was understood that the effect of stretching was greater when performing ballistic stretching techniques.

Purpose : The purpose of this study was to determine the effects of hip adduction using a ball on the activation of the vastus medialis oblique (VMO) and the vastus lateralis (VL) during dynamic semisquat exercises. Methods : Twenty seven participants performed three repetitions of a double-leg semisquat and squeeze semisquat (semisquat with hip adduction using a ball) at $60^{\circ}$ knee flexion. The activation of the VMO and the VL was recorded at dominant leg during both semisquat exercises using surface electromyography (MP 100). EMG data were normalized to the maximal voluntary isometric contraction (MVIC) of the quadriceps produced during seated, isometric knee extension. Results : Results of paired t-test analyses revealed that there were no differences between activity of the VMO and the VL in both double-leg semisquat and squeeze semisquat. The activity of the VMO was significantly increased in squeeze semisquat whereas there was no difference in activity of the VL between double-leg semisquat and squeeze semisquat. Conclusion : Combining hip adduction using a ball with semisquat at $60^{\circ}$ knee flexion preferentially increases the activity of the VMO. We can conclude that semisquat at $60^{\circ}$ knee flexion with hip adduction using a ball selectively recruits the VMO. Rehabilitation for quadricep imbalance should consider these findings when selecting exercises which could preferentially activate the VMO.

Purpose : This study investigates the effects on balanced ability and ankle joint muscle following balance pad and trampoline training periods in order to report a clinical directing about this matter. Methods : A total of nine members participated in a balance training program that put a balance pad and trampoline to use. Participants trained three times a week for thirty minutes in groups of six. Resting time was set for two minutes. EMG (median frequency and root mean square) was used to measure muscle activity at 3 weeks and 6 weeks, respectively. The tibialis anterior and gastrocnemius muscles were measured. Participants were measured with eyes open and closed. Results : The median frequency showed a significant difference according to the change in time in both muscles. Also, results showed a significant interaction between eyes open and closed in the gastrocnemius muscle. The root mean square only showed a significant difference according to the change in time in the gastrocnemius muscle. Conclusion : We suggest that the balance pad and trampoline training influence a decrease in the recruitment rate of slow twitch muscles through an improvement in balance ability; however, the training did not show a statistically significant difference with regards to eyes open and closed.

Purpose : This study aims to examine the influences of galvanic vestibular stimulation on autonomic reaction of normal adults. Methods : Participants in this research totaled 28 (14 men and 14 women). Galvanic vestibular stimulation was conducted with a binaural electrode configuration for 60 sec. Galvanic vestibular stimulation measurements were conducted with the subjects in a prone position. Measured items included skin conductance, blood flow, pulse rate, and respiratory rate. Measurements were repeated for a total of five times, before application, during application, after application, 5 minutes after application and 10 minutes after application. Results : Skin conductance reaction showed statistically significant differences in changes depending on time after galvanic vestibular stimulation and there were statistically differences in changes of blood flow, pulse rate and respiratory rate after galvanic vestibular stimulation. Conclusion : Blood flow, pulse rate and respiratory rate of autonomic reactions were not influenced by galvanic vestibular stimulation, but skin conductance reaction was influenced by it and it was found that it was reduced during and after stimulation rather than before stimulation. Consequently, it was considered that galvanic vestibular stimulation affected the autonomic reaction.

Purpose : The purpose of this study was to investigate knee muscle strength, balance, and proprioception by walking while giving weight to the ankle joint at a load of 0%, 10%, and 15% gradient on a treadmill. Methods : Twenty-four subjects were divided into three groups. Group A walked on a 0% gradient while giving weight to the ankle joint as a load. Group B walked on a 10% gradient while giving weight to the ankle joint as a load. Group C walked on a 15% gradient while giving weight to the ankle joint as a load. This was performed three times per week for four weeks. The walking speed was set at 4km/hour and the walking time was set at 20 minutes. Measurements were performed before and after the experiment. Biodex medical system and Balance system SD were used as measuring instruments. Results : There was no significant difference between the gradients in muscle strength, balance and proprioception. However, there were differences in pretest and posttest measurements for muscle strength, balance and proprioception in each gradient. In particular, the gradient of 10% showed a significant difference. Conclusion : According to the results of this study, to use a 10% gradient is effective when walking while giving weight to the ankle joint as a load.

Purpose : We investigated the effects of the insole types on lower leg muscle activation during treadmill walking. The three insole types investigated for this study were normal insole, medial wedge insole, and viscoheel. Methods : Participants were assigned into three groups. People with foot transformation were excluded from this study. Each participant walked for ten minutes. The first day we applied a normal insole. On the second day, a medial wedge insole was applied. Finally, on the last day a viscoheel was applied. After walking on a treadmill for ten minutes, we measured muscle activation in lower leg muscles (gastrocnemius and tibialis anterior). Surface electromyography (EMG) was used to measure muscle activity. The data were analyzed using one-way analysis of variance (ANOVA) with repeated measures to determine the statistical significance. Results : The results of this study were summarized as follows. While walking on the treadmill, root mean square (RMS) values of the gastrocnemius when the viscoheel was applied were significantly lower than the other insole types. There was no significant difference for the RMS values for the tibialis anterior using viscoheel. The normal insole and viscoheel insole were significantly different in a post hoc analysis. However, there was no significant difference for normal insole and medial wedge insole. Conclusion : Using a viscoheel insole decreases muscle activity of the lower leg. Therefore, in conclusion, the viscoheel insole type reduces the load on the lower leg during walking.

Purpose : The purpose of this study was to analyze skin reactions induced by ultraviolet irradiation using digital imagery. Methods : We recruited 15 women and ultraviolet irradiation was applied to their lumbar area. (The degree of inflammatory reaction was set on the basis of the third erythema dose. Image analysis was divided by Photoshop CS (8 bit RGB scale and gray scale). Then, images were processes using Image Pro Plus 4.5 program analyzing R, G, B, chromatic red value, luminance value and gray value. Results : As a result of analyzing changes in RGB scale, there were statistically significant differences in R, G, and chromatic red values. As a result of analyzing changes in gray scale, there were statistically significant differences in gray value. Analysis of changes in B and luminance values showed that there was no statistically significant difference. Conclusion : This study found that ultraviolet irradiation had influence on RGB and gray scale. These results suggest that changes to digital images on skin reaction by ultraviolet irradiation are related to erythema. In particular, these changes are related to R and gray values.