Background: Many trials have been conducted the methods and types of intervention of form rollers, but no research has been done yet that mixes the methods and types of intervention. Objectives: To analyze the effects of myofascial release on the improvement of range of motion (ROM), flexibility, pain pressure threshold, and balance. Design: Randomized controlled trial. Methods: All subjects measured ROM, flexibility, pressure pain threshold, and dynamic balance by pre-test. After pre-test, subjects were randomized that static-vibration foam rolling group (n=12), dynamic-vibration foam rolling group (n=12), general foam rolling group (n=12). For the intervention, 3 sets of 90 seconds were applied to each group, and rest time was set to 60 seconds between sets. In the post-test and follow-up test after 10 minutes, all three groups were measured the ROM, flexibility, pressure pain threshold, and dynamic balance. Results: The results of comparing ROM, flexibility, pressure pain thresholds, dynamic balance ability appeared higher significant difference in the prepost- 10 minutes follow up test in comparison between time in the intragroup (P<.001). As a result of comparing the change of pre-post-10 minutes follow up, static vibration foam rolling showed higher significant difference compared to control groups (P<.001). Conclusion: Through this study, when foam rolling is applied within the same intervention time, static foam rolling can be expected to have a better effect than the existing dynamic foam rolling as well as vibration foam roller can expect better effect than general foam rolling.

Background: The hamstring muscles in the lower extremity are highly important for knee joint stability and can be classified into medial and lateral hamstrings according to the anatomical position, which have some different functions. To measure the strength of the individual hamstring muscles, manual muscle testing is clinically performed by dividing rotation postures into internal and external postures. However, this has no sufficient scientific background. Objects: This study aimed to test the difference that the tibial rotation would cause in the muscle activity of the medial and lateral hamstrings. Methods: The muscle activities of the biceps femoris, semitendinosus, and semimembranosus were measured in a total of three different postures (neutral position and internal and external rotations) with 3 replications. During the maximal isometric contraction, resistance was constantly provided by the string attached to the strap, not by manual resistance of the examiner. Before and after electromyography measurements, the participants underwent hamstring flexibility measurement using the active knee extension test in the supine position on the treatment table Results: The semitendinosus had a 12.56% reduction in muscle activity in external rotation as compared with that in neutral position. The biceps femoris and semimembranosus showed reduced muscle activities in both external and internal rotations as compared with those in neutral position. Only the women showed significant decreases in the comparison between pre and post-active knee extension. Conclusion: Only the semitendinosus muscle was consistent with the anatomical speculation. However, the reduction in the muscle activity of the semitendinosus as compared with that in neutral position was only 12.56%, the clinical value of which may be difficult to justify.

Background: To improve muscle flexibility, static stretch is the most common type and is considered safe and effective for improving overall flexibility of muscles. During the stretch, the intensity is more likely to be determined by the degree of an athlete’s pain and practitioner’s skills rather than quantitative measures of stretch. It is necessary to determine the optimal intensity for the stretch. Objects: The purpose of this study is to explore the relationship between hand held dynamometer (HHD) and verbal rating scale (VRS) in comparison of the effects of continuance time on active (walking) and inactive (sitting) movement after static stretch. Methods: A cross-sectional study was conducted with a sample (n=62) recruited from a university. Participants were randomly assigned to 2 different groups (n=31 for each group) based on participants’ positions either remaining in sitting or freely walking around for a series of re-assessments. Data was collected at pre-warm up, pre-stretch, post-stretch, and additional assessments at the time of 3, 6, 9, 12, 15, 20 and 30 minutes after the stretch. Results: Relationship between VRS and HHD scores represents very weak correlation (Spearman’s p=-.16, p>.05). Pearson’s correlation analysis was conducted following the logarithmic transformation of the two scores. Pearson’s correlation after the transformation still showed a very low relationship and a poor linear relationship between the two scores (Pearson’s r=-.18, p>.05). Conclusion: The optimal intensity for stretch cannot be solely determined by the subjective pain perception. The objective measurement such as HHD could be used in conjunction with the pain perception.