Changes in Speed Skating Velocity in Relation to Push-Off Effectiveness
Changes in Speed Skating Velocity in Relation to Push-Off Effectiveness
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DOI:
10.1123/ijspp.8.2.188
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发表时间:
2013-03-01
影响因子:
3.3
通讯作者:
de Koning, Jos J.
中科院分区:
文献类型:
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作者:
Noordhof, Dionne A.;Foster, Carl;de Koning, Jos J.
Speed skating posture, or technique, is characterized by the push-off angle or effectiveness (e), determined as the angle between the push-off leg and the ice; the preextension knee angle (theta(0)); and the trunk angle (theta(1)). Together with muscle-power output and environmental conditions, skating posture, or technique, determines velocity (v). Purpose: To gain insight into technical variables that are important to skate efficiently and perform well, e, theta(0), theta(1), and skating v were determined every lap during a 5000-m World Cup. Second, the authors evaluated if changes (Delta) in e, theta(0), and theta(1) are associated with Delta v. Methods: One camera filmed the skaters from a frontal view, from which e was determined. Another camera filmed the skaters from a sagittal view, from which theta(0) and theta(1) were determined. Radio-frequency identification tags around the ankles of the skaters measured v. Results: During the race, e progressively increased and v progressively decreased, while theta(0) and theta(1) showed a less consistent pattern of change. Generalized estimating equations showed that Delta e is significantly associated with Delta v over the midsection of the race (beta = -0.10, P