Background: Previous studies have been reported that when instrument assisted soft tissue mobilization (IASTM) and the self-myofascial release technique were used on the muscles. However, studies that applied the IASTM and self-stretching to the gastrocnemius muscle are thought to be necessary but there is no such previous study. Objectives: To investigate the effects of IASTM and self-stretching on gastrocnemius muscle thickness and the range of motion of joint in dorsiflexion in healthy college student. Design: Quasi-experimental design (single blind). Methods: The subjects were healthy college students in their 20s with a healthy body. As for the experimental method in this study, comparison between before and after the experiment was performed to compare the effects of myofascial release using IASTM and stretching. The preliminary survey investigated the range of motion (ROM) of ankle joint of the subjects. The thicknesses of gastrocnemius muscles were measured using ultrasonography. One day after the preliminary survey, IASTM interventions and self-stretching interventions were randomly selected. If IASTM intervention is selected, the IASTM of the gastrocnemius muscle was applied for 5 minutes. After than, muscle thickness and the ankle dorsiflexion ROM were measured. Subjects were asked to take a break for about one day after performing the intervention. Self-stretching was applied to the gastrocnemius muscle for 5 minutes identically. After than, muscle thickness and the ankle dorsiflexion ROM were measured. Results: The thickness of the gastrocnemius muscle decreased significantly IASTM intervention, and the ankle dorsiflexion ROM increased significantly IASTM intervention. Ankle dorsiflexion ROM increased significantly the selfstretching intervention. The amounts of change in ankle dorsiflexion ROM through the IASTM was significantly greater than that through self-stretching. Conclusion: In order to immediately increase muscle flexibility in a short time, the IASTM is more effective although the self-stretching method is also effective.

Various surface colors are predicted and implemented using the interference color generated by controlling the thickness of nano-level diamond like carbon (DLC) thin film. Samples having thicknesses of up to 385 nm and various interference colors are prepared using a single crystal silicon (100) substrate with changing processing times at low temperature by plasma-enhanced chemical vapor deposition. The thickness, surface roughness, color, phases, and anti-scratch performance under each condition are analyzed using a scanning electron microscope, colorimeter, micro-Raman device, and scratch tester. Coating with the same uniformity as the surface roughness of the substrate is possible over the entire experimental thickness range, and more than five different colors are implemented at this time. The color matched with the color predicted by the model, assuming only the reflection mode of the thin film. All the DLC thin films show constant D/G peak fraction without significant change, and have anti-scratch values of about 19 N. The results indicate the possibility that nano-level DLC thin films with various interference colors can be applied to exterior materials of actual mobile devices.

Background: Few comparative studies have been conducted on strengthening the anterior and posterior muscles of the trunk via lumbar stabilization exercises. Objectives: To compare the effects of forward leaning exercise and supine bridging exercise in stability exercise. Design: Randomized controlled clinical trial (single blind). Methods: Thirty subjects with spondylolisthesis were participated in this study. Fifteen subjects performed the bridging exercises and fifteen subjects performed the forward leaning exercises. Each exercise was held for ten seconds per repetition, and four repetitions were considered one sub-session. A total of four sub-sessions were performed in one full exercise session. The full exercise session required thirty minutes, including rest time. Trunk strength and range of motion and Oswestry disability index were measured. Results: Two weeks later, trunk flexion strength and trunk extension range of motion were significantly increased in the forward leaning exercise group than in the supine bridging group, trunk extension strength were significantly increased in the supine bridging exercise group than in the forward leaning group. After two weeks, the pain score was significantly lower in the forward leaning exercise group than in the supine bridging group. Conclusion: This study has shown that stabilization exercises are effective in increasing range of motion and strength in spondylolisthesis subjects. It was especially confirmed that the method of strengthening the anterior muscles of the trunk is more effective than the standard stabilization exercise method.

Background : Methods of wearing a baby carrier have suggested; however, there have been no studies suggesting ideal ways. Objective : To investigate muscular fatigue and balance of the waist during baby carrier are worn on the front, the side, and the back of the body. Design: Randomized controlled clinical trial (single blind) Methods : The subjects of this study were 20 healthy men and women in their 20s, who underwent tests of muscular fatigue and balance of the waist bones based on types of wearing baby carrier. Electromyogram (EMG) patches were attached to the L2 and the L4 for testing muscular fatigue, while a device for measuring proprioceptive senses was used to assess balance ability. The measurements were performed before wearing the baby carrier and after 30 minutes of normal walking. The methods of wearing the baby carrier included wearing on the front, the side, and the back of the body. Results : The time taken to adjust the balance was shorter than other types of wearing during the baby carrier were worn on the side, and the ratio of lumbar flexion and relaxation was shown insignificant. Conclusions : These results suggested that wearing the carriers on the side was most effective on reducing fatigue and enhancing balance ability of the waist.