The Influence of Ankle Inversion Angle on Trunk Muscle Activity during Squat Exercise

摘要

Objectives: To see the trunk muscle activation during squat exercise in accordance with the inversion angle. Methods/Statistical Analysis: After previous research, we recruited healthy adult of 12 males and 12 females (The mean age 20.7±1.66, a total of 24 adults) who agreed to participate in this study. This study measured External Oblique abdominis (EO), Transverse Abdominis (TrA), Eractor Spinae (ES), Multifidus (MF) muscle activation during the squat exercise according to four inversion angles (0°, 10°, 15°, 20°). In order to calculate the subject characteristics, the mean value and the standard deviation of all the variables of the subjects, descriptive statistics were employed. One-way repeated ANOVA was used to compare muscle activities of EO, TrA, ES and MF depending on the four inversion angles. Bonferroni’s correction was used as post-hoc comparison and statistical significance level was set at α = .05. Findings: In EO, there was significant difference on four inversion angles (p<.001). Post-hoc test result showed significant difference (p<.001) on four inversion angles between 0°-10°, 0°-15°, 0°-20°, 10°-15° and 15°-20°. In TrA, there was significant difference on four inversion angles (p<.001) as well. Post-hoc test result indicated significant difference(p<.001) on four inversion angles between 0°-15°, 0°-20°, 10°-15° and 10°-20°. In ES and MF, they did not show significant difference in every inversion angle. Also, post-hoc test result did not reveal significant difference between every intervention. This study has been conducted to see the change of trunk muscle activation in accordance with inversion angle during squat exercise. In order to investigate the changes, we compared global and local muscles of trunk by applying the four inversion angles (0°, 10°, 15°, 20°). Since lower extremity or trunk global muscle activation has been studied a lot already, we put difference by measuring local muscle additionally during squat exercise. There were lots of studies about lower extremity and trunk muscle activation using squat exercise. In this research, however, the back muscle did not show a significant difference during squat exercise. These results mean that back muscle is not that significant in the squat exercise with altering inversion angles. Also, we experimented with the traditional squat exercise and added an intervention of changing the inversion angle. However, we presume that if we provide a variety of intervention on the trunk position, or require a trunk flexion or extension, there would be another result on the back muscle. Thus, more research, related with trunk position as well as ankle position, needs to be carried out continuously. Application/Improvements: In conclusion, squat exercise with inversion angle is an effective exercise method in that it can cause the activation of both global and local muscle of the abdomen. Also, the inversion angle of 15° is the most ideal one to activate the trunk muscle with effectiveness without ankle inversion injury. Therefore, the squat exercise with the varying inversion angles will be helpful to maintain trunk stability for the position through time effectiveness.