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Kobayashi R1, Urabe Y1, Sasadai J1, Fukui K1, Komiya M1, Numano S1, Maeda N1
1Hiroshima university, Graduate School of Biomedical and Health Sciences, Department of Sports Rehabilitation, Hiroshima, Japan
Background: In sports, agility is necessary to move quickly than opponents. Choice reaction time (CRT) is commonly measured to assess agility. Standing posture has been said to affect agility (Kishikawa 2014). Loading on the ball of the foot is one of the teaching methods of standing posture and important to change direction smoothly. However, the effect of loading on the ball of the foot in CRT has not been cleared.
Purpose: This study aimed to investigate the effect of loading on the ball of the foot in CRT from the viewpoint of muscle activities.
Methods: Twelve healthy men participated in this study. The subjects performed side step. CRT was defined as the time at which both feet left the center mat of Reaction MR (Takei Inc.) after light stimulation. CRT was measured under the following three conditions: upright posture (UP), normal standing posture (NP), and loading on the ball of the foot standing posture (LP). NP and LP were defined as 55 ° flexion of hip joint and 50 ° flexion of knee joint. When CRT was measured, preparatory muscle activities, muscle activities during side step, and the onset of muscle activities were measured using Personal-EMG plus (Oisaka Electronic Equipment Ltd.). Test muscles were vastus medialis, gastrocnemius, and peroneal longus of the right leg. Maximal voluntary contraction (MVC) of three muscles were measured and preparatory muscle activities and muscle activities during CRT were normalized with MVC. Statistical analysis was conducted using one way ANOVA. The significance level was set at 5%.
Results: CRT was 771.0 ± 36.3 ms in UP, 727.4 ± 29.5 ms in NP, and 686.5 ± 39.0 ms in LP. CRT in LP was shortened by 5.6% as compared with in the NP (p 0.05). The preparatory muscle activities of vastus medialis and peroneal longus in LP were significantly increased as compared with those in UP and NP (p 0.05). The muscle activities of the vastus medialis and peroneal longus in LP was significantly increased as compared with in UP and NP (p 0.05). The onset of muscle activities of vastus medialis, gastrocnemius, and peroneal longus was significantly shortened in LP as compared with UP and NP (p 0.05).
Conclusion(s): Previous studies reported that increased preparatory muscle activities lead to the shortening of the onset of muscle activities and to increase in muscle activities during the action (Kimura et al. 2002). In this study, by loading on the ball of the foot, increased preparatory muscle activities were observed in vastus medialis and peroneal longus. The muscle activities of vastus medialis increase at the side step and peroneal longus plays a role of moving the center of gravity laterally. In conclusion, CRT was thought to be shortened by increasing muscle activities and shortening of the onset of muscle activities during side step. Our results suggest that the lateral CRT could be shortened by loading on the ball of the foot in the standing posture.
Implications: This research could be useful for teaching standing posture that enables quick movement in sports.
Keywords: Muscle activity, Loading on the ball of the foot, Choice reaction time
Funding acknowledgements: We have no funding acknowledgement in this study.
Purpose: This study aimed to investigate the effect of loading on the ball of the foot in CRT from the viewpoint of muscle activities.
Methods: Twelve healthy men participated in this study. The subjects performed side step. CRT was defined as the time at which both feet left the center mat of Reaction MR (Takei Inc.) after light stimulation. CRT was measured under the following three conditions: upright posture (UP), normal standing posture (NP), and loading on the ball of the foot standing posture (LP). NP and LP were defined as 55 ° flexion of hip joint and 50 ° flexion of knee joint. When CRT was measured, preparatory muscle activities, muscle activities during side step, and the onset of muscle activities were measured using Personal-EMG plus (Oisaka Electronic Equipment Ltd.). Test muscles were vastus medialis, gastrocnemius, and peroneal longus of the right leg. Maximal voluntary contraction (MVC) of three muscles were measured and preparatory muscle activities and muscle activities during CRT were normalized with MVC. Statistical analysis was conducted using one way ANOVA. The significance level was set at 5%.
Results: CRT was 771.0 ± 36.3 ms in UP, 727.4 ± 29.5 ms in NP, and 686.5 ± 39.0 ms in LP. CRT in LP was shortened by 5.6% as compared with in the NP (p 0.05). The preparatory muscle activities of vastus medialis and peroneal longus in LP were significantly increased as compared with those in UP and NP (p 0.05). The muscle activities of the vastus medialis and peroneal longus in LP was significantly increased as compared with in UP and NP (p 0.05). The onset of muscle activities of vastus medialis, gastrocnemius, and peroneal longus was significantly shortened in LP as compared with UP and NP (p 0.05).
Conclusion(s): Previous studies reported that increased preparatory muscle activities lead to the shortening of the onset of muscle activities and to increase in muscle activities during the action (Kimura et al. 2002). In this study, by loading on the ball of the foot, increased preparatory muscle activities were observed in vastus medialis and peroneal longus. The muscle activities of vastus medialis increase at the side step and peroneal longus plays a role of moving the center of gravity laterally. In conclusion, CRT was thought to be shortened by increasing muscle activities and shortening of the onset of muscle activities during side step. Our results suggest that the lateral CRT could be shortened by loading on the ball of the foot in the standing posture.
Implications: This research could be useful for teaching standing posture that enables quick movement in sports.
Keywords: Muscle activity, Loading on the ball of the foot, Choice reaction time
Funding acknowledgements: We have no funding acknowledgement in this study.
Topic: Sport & sports injuries
Ethics approval required: Yes
Institution: Hiroshima University
Ethics committee: Hiroshima University Committee on Ethics in Clinical Research
Ethics number: E-1076
All authors, affiliations and abstracts have been published as submitted.
