Ground Force Direction for Optimal Performance Using a Standing Start. Both the moving start and variations of the standing start are utilized in baseball, basketball, soccer, field hockey, lacrosse, rugby and other sports. Athletes who either lack the strength needed for the forceful push off both feet required during the 3- or 4-point starting stance, or have not mastered the correct form and technique, can often improve their times in a short sprint by utilizing a standing start. This also places the front foot closer to the starting line, is more forgiving, easier to master, and moves the body into the correct sprint position within the first two steps with less ground reaction force than what is required from a crouched position. The study described below examined the connection between ground reaction impulses and sprint acceleration when the standing start was used and offers training advice for the improvement of horizontally-directed ground reaction force.
Large horizontal acceleration in short sprints is a critical performance parameter for many team sports athletes. It is often stated that producing large horizontal impulse at each ground contact is essential for high short sprint performance, but the optimal pattern of horizontal and vertical impulses is not well understood, especially when the sprints are initiated from a standing start.
This study was an investigation of the relationships between ground reaction impulses and sprint acceleration performance from a standing start in team sports athletes. Thirty physically active young men with team sports backgrounds performed 10-m sprints from a standing start, whereas sprint time and ground reaction forces were recorded during the ﬁfirst ground contact and at 8 m from the start. Associations between sprint time and ground reaction impulses (normalized to body mass) were determined by a Pearson’s correlation coefﬁcient (r) analysis. The 10-m sprint time was signiﬁcantly ( p 0.01) correlated with net horizontal impulse (r =20.52) and propulsive impulse (r =20.66) measured at 8 m from the start. No signiﬁcant correlations were found between sprint time and impulses recorded during the ﬁrst ground contact after the start. These results suggest that applying ground reaction impulse in a more horizontal direction is important for sprint acceleration from a standing start. This is consistent with the hypothesis of training to increase net horizontal impulse production using sled towing or using elastic resistance devices, which needs to be validated by future longitudinal training studies.
Increasing ground reaction force in a horizontal direction, using the Austin leg-drive machine, weighted sleds, and band resistance, is recommended to improve speed in the standing start and early acceleration phase of a short sprint.
Naoki Kawamori, Kazunori Nosaka, and Robert U. Newton. 2013. Relationships between ground reaction impulse and sprint acceleration performance in team sport athletes. Journal of strength and Conditioning research 27(3)568-573.