Kinematic analysis of the backstroke start: differences between backstroke specialists and non-specialists
(Kinematische Analyse des Starts im Rückenschwimmen: Unterschiede zwischen Rückenspezialisten und Nicht-Spezialisten)
The purpose of this study was to clarify factors to perform the hole-entry technique in the backstroke start. A total of 16 well-trained Japanese competitive swimmers were divided into two groups (backstroke specialists and non-specialists) to compare their backstroke start motions. Their backstroke motions were videotaped, and two-dimensional co-ordinates for the swimmers were obtained from the video images using direct linear transformation methods. A non-paired t-test and Mann-Whitney U-test were used to analyse the statistical difference of the kinematic variables between the groups. Backstroke specialists showed a significantly shorter 5 m time (P = 0.009, effect size = -1.54), a significantly higher position of the toe (P = 0.010, effect size = 1.47) at signal and of the hip at toe-off (P = 0.002, effect size = 1.94), a significantly larger hip joint angle at toe-off (P = 0.007, effect size = 1.60) and a significantly higher angular velocities of the hip joints (45-85%; P < 0.05) for the normalised time as compared to that of non-specialists. An earlier initiation of the extension and the maintenance of a higher extension speed at the hip joints were important factors in achieving an arched-back posture, which facilitated and water entrance with a small entry range.
© Copyright 2014 Journal of Sports Sciences. Taylor & Francis. Alle Rechte vorbehalten.
Schlagworte: | Biomechanik Bewegungsmerkmal Technik Schwimmen Rückenschwimmen Start |
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Notationen: | Ausdauersportarten |
DOI: | 10.1080/02640414.2013.845678 |
Veröffentlicht in: | Journal of Sports Sciences |
Veröffentlicht: |
2014
|
Jahrgang: | 32 |
Heft: | 7 |
Seiten: | 635-641 |
Dokumentenarten: | Artikel |
Sprache: | Englisch |
Level: | hoch |