Metatarsophalangeal Joint Movement in Olympic Sprinters
Notice bibliographique
Résumé
Introduction: In sprinting, the metatarsophalangeal (MP) joint flexes as an athlete rolls onto the forefoot but does not extend until after take-off (Stefanyshyn and Nigg, 1997). As a result, energy absorbed at the MP joints is substantial, however, the energy produced in the second half of the stance-phase at this joint is minimal. Since the absorbed energy is dissipated and not stored for later re-use, one could speculate that a reduction of such energy absorption may lead to an increase in performance. That is, if all the energy can be directed toward the movement task and not wasted on auxiliary tasks, performance may be improved. The amount of energy absorbed at the MP joint is a function of both the moment generated about the joint as well as the maximal joint movement. Thus, if either of these variables is decreased, the amount of energy absorbed at the MP joint should be decreased, potentially resulting in an increase in performance. Therefore, the purpose of this investigation was to determine the relationship between metatarsophalangeal joint movement and sprinting performance during an elite competition. Methods: Kinematic data were recorded during the heats, semi-final and final races of the mens and womens 100m sprints at the 2000 Sydney Olympic Games. In total, measurements were performed on 70 athletes (50 males and 20 females). The data were collected at approximately the 60m mark of the race using two high-speed digital cameras (JVC 9800) sampling at 120 Hz. Both cameras were set with the fields of view focussed on a 1.5m section of track. The first camera was focused between lanes 3 and 4 while the second camera was focused on lanes 6 and 7. The video data were hand digitised and the MP joint angle was defined as the angle between the plantar surface of the forefoot and rearfoot of the shoe. A correlational analysis was performed to quantify the relationship between MP joint bending and sprint performance. Results: The average peak extension at the MP joint was similar between males and females, 36.5° and 37.7° respectively. Very low and non-significant correlations were found between peak extension at the MP joint and 100m sprint time for both male (r = 0.351, p = 0.994) and female (r = 0.180, p = 0.777) athletes. Discussion: On average, during competition the MP joint underwent a large range of movement, which corresponded well with values previously reported from in lab testing (Stefanyshyn and Nigg, 1997). Similar to the in lab testing, the athletes only flexed their MP joint minimally at take-off. It has been shown that increasing the bending stiffness of a shoe and decreasing the extension of the MP joint leads to improvements in vertical jump performance (Stefanyshyn and Nigg, 2000). However, there was no relation between the maximal extension of the MP joint and sprinting performance in this study. Thus, it may be that the concept of reducing the energy lost does not apply to sprinting performance. However, recent pilot studies with increased bending stiffness in sprint shoes have shown positive improvements in sprinting performance. Alternatively, it is possible that kinematics alone may not be sufficient to predict performance measures in sprinting. Further investigation into the kinetics and energy absorption at the MP joint is necessary to fully understand the role of the MP joint in sprinting performance. Acknowledgements: Funding for this study was provided from a grant by the International Olympic Committee, Medical Commission.
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| Catégorie | Codex | Gemma |
|---|---|---|
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Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
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