vertical impulse, have a longer total contact time, and that the increased linear impulses would occur during the impact interval as a result of increased RF magnitude and contact time. We tested these hypotheses by measuring the horizontal and vertical RFs during the takeoff of a long jump and comparing
Christopher D. Ramos, Melvin Ramey, Rand R. Wilcox, and Jill L. McNitt-Gray
Travis J. Peterson, Rand R. Wilcox, and Jill L. McNitt-Gray
Our aim was to determine how skilled players regulate linear and angular impulse while maintaining balance during the golf swing. Eleven highly-skilled golf players performed swings with a 6-iron and driver. Components contributing to linear and angular impulse generated by the rear and target legs (resultant horizontal reaction force [RFh], RFh-angle, and moment arm) were quantified and compared across the group and within a player (α = .05). Net angular impulse generated by both the rear and target legs was greater for the driver than the 6-iron. Mechanisms used to regulate angular impulse generation between clubs varied across players and required coordination between the legs. Increases in net angular impulse with a driver involved increases in target leg RFh. Rear leg RFh-angle was maintained between clubs whereas target leg RFh became more aligned with the target line. Net linear impulse perpendicular to the target line remained near zero, preserving balance, while net linear impulse along the target line decreased in magnitude. These results indicate that the net angular impulse was regulated between clubs by coordinating force generation of the rear and target legs while sustaining balance throughout the task.
Antonia M. Zaferiou, Rand R. Wilcox, and Jill L. McNitt-Gray
This study determined how dancers regulated angular and linear impulse during the initiation of pirouettes of increased rotation. Skilled dancers (n = 11) performed single and double pirouette turns with each foot supported by a force plate. Linear and angular impulses generated by each leg were quantified and compared between turn types using probability-based statistical methods. As rotational demands increased, dancers increased the net angular impulse generated. The contribution of each leg to net angular impulse in both single and double pirouettes was influenced by stance configuration strategies. Dancers who generated more angular impulse with the push leg than with the turn leg initiated the turn with the center of mass positioned closer to the turn leg than did other dancers. As rotational demands increased, dancers tended to increase the horizontal reaction force magnitude at one or both feet; however, they used subject-specific mechanisms. By coordinating the generation of reaction forces between legs, changes in net horizontal impulse remained minimal, despite impulse regulation at each leg used to achieve more rotations. Knowledge gained regarding how an individual coordinates the generation of linear and angular impulse between both legs as rotational demand increased can help design tools to improve that individual’s performance.
Travis J. Peterson and Jill L. McNitt-Gray
impulse perpendicular to the target was found to be maintained near 0, while net linear impulse parallel to the target was less toward the target as players hit swings with a driver compared with a 6-iron. This coordination strategy implies a specific role of each leg during the golf swing. The regulation