title: Backstroke organization in physical education students as a function of skill and sex.
abstract: This study assessed how stroking in backstroke varies with performance status and sex. A total of 36 subjects were separated into two groups of 18 by sex and further divided into two subgroups of nine, faster and slower, based on velocity in the 100-m event. Stroking parameters and coordination indexes were measured at this 100-m pace. Index 1 characterizes the continuity between propulsive phases of each arm and Index 2, the simultaneity between the beginning of the pull of one arm and of the recovery of the other arm. It is shown that the entry-catch and clearing vary (p<.05) between men (4.5%+/-3.7 and 27.1%+/-9.0) and women (8.3%+/-8.5 and 20.0%+/-4.6). Index 1 indicates that women have a better continuity than men (7.4%+/-6.3 vs -10.7%+/-3.6; p<.05). Performance is mainly explained (p<.05) by the increase in the entry and catch (r=.58 for men and .75 for women) at the expense of clearing (respectively, r=-.70 and -.53, p<.05). For men, Index 2 indicates that the simultaneity is higher in faster than in slower swimmers (10.6+/-7.0% vs 15.5+/-7.4%; p<.05) and is correlated with performance (r=-.47, p<.05). Index 2 is related to the clearing (r=.71), the number of kicks per cycle (K x C(-1), r=-.61), and the pull (r=.60). For women, the performance is explained by Index 1 (r=.48, p<.05). Index 1 is related (p<.05) to stroke rate (r=.84), the clearing (r=-.70), and K x C(-1) (r=-.61). K x C(-1) increases from 6.4+/-.70 for the faster to 7.8+/-2.0 for the slower group (p<.05).
authors.affiliation: Faculté des Sciences du Sport, Université de la Méditerranée, Marseille. robert.lerda@wanadoo.fr
authors.forename: Robert
authors.initials: R
authors.lastname: Lerda
authors.forename: Chantal
authors.initials: C
authors.lastname: Cardelli
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Coudereau
mesh_terms: D000328:Adult; D001076:Aptitude / Q000502:physiology; D001696:Biomechanical Phenomena; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D010806:Physical Education and Training / Q000706:statistics & numerical data; D005082:Physical Exertion / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology; D012737:Sex Factors; D013334:Students / Q000706:statistics & numerical data; D013550:Swimming / Q000502:physiology*; D013647:Task Performance and Analysis