Effect of Power Grasping on Muscle Activity of Trunk during One Leg Stance

PURPOSE: This study investigated the effects of trunk muscle activity with power grasping during one leg stance. METHODS: Twenty-eight subjects participated in this study. Subjects were divided into two groups, one that performed power grasping, and another that did not. An investigator measured the activities of a subject's trunk muscle such as internal oblique (IO), external oblique (EO), erector spinae (ES), and gluteus medius (GM) while a subject was doing one leg stance. RESULTS: An independent t-test was used to analyze trunk muscle activities with power grasping during one leg stance between the experimental group and the control group. Only the EO activity differed significantly between groups (p<0.05). CONCLUSION: The results indicate that one leg stance with power grasping affected trunk muscle activity. Therefore, this is a useful method for providing lumbar spine stability.

Comparison of Trunk Strategy to Maintain Balance during the One-Leg Stance on a Medio-Lateral Ramp and an Anterior-Posterior Ramp

PURPOSE: This study examined two trunk strategies - medio-lateral ramp and anterior-posterior ram - and their effects on pelvis and trunk movements, providing basic material for safe ramp utilization. METHODS: The present study included 20 asymptomatic males recruited from a local university. Participants were asked to stand with their feet shoulder-width apart. Their dorsal side faced the camera, and measurements were performed while standing in a neutral double stance, one leg stance, 15° of medial and lateral ramp, and 15° of anterior and posterior ramp. Participants were allowed to practice for 3 minutes, and each participant had a 30 seconds rest between the two ramp conditions. One-way repeated measures analysis of variance was used to determine the effects the ramp conditions on spinal alignment. In all analyses, p<0.05 was used to indicate statistical significance. RESULTS: The trunk-inclination angle on the posterior ramp was significantly lower than that of the double stance position (p<0.05). The trunk imbalance angle was significantly higher on the medial ramp, than that on the double stance position (p<0.05). The pelvic position and pelvic torsion angles were significantly higher in the medial, lateral, and anterior ramp positions than that of the double stance position (p<0.05). The pelvic rotation angles on the medial, lateral, and anterior ramps were significantly lower than that of the double stance position (p<0.05). CONCLUSION: These findings suggest that when people are exposed to the same form of ramp for an extended period, posture modifications may be triggered.