Purpose: This study analyzed kinematic changes during a 100-m front crawl to investigate the effects of performance level and gender, comparing 12 high-speed males, 8 medium-speed males, 8 low-speed males, and 8 high-speed females.
Methods: Assessments were made throughout the race in a 25-m pool divided into five zones of 5 m. Velocity (V), stroke rate (SR), and stroke length (SL) were calculated for each 25-m length (L1 to L4) and for each 5-m zone. Four stroke phases were identified by video analysis, and the index of coordination (IdC) was calculated. Three modes of arm coordination were identified: catch-up, opposition, and superposition. The leg kick was also analyzed.
Results: The high-speed male swimmers were distinguished by higher V (1.89 m·s−1), SR (0.78 Hz), SL (2.16 m per stroke), propulsive phase (54%), and IdC (3.8%) (P < 0.05), and by the stability of these values throughout the race. The medium- and low-speed males had an opposition coordination (−1% < IdC < 1%) during the third length of the 100 m. Because of fatigue in length 4, they spent more time with the hand in the push phase (possibly because of a decrease in hand velocity) and changed to superposition coordination (medium-speed males: IdC = 2.78%; low-speed males: IdC = 1.12%) (P < 0.05). This change was ineffective, however, as SL continued to decrease throughout the 100 m (P < 0.05). The main gender findings were the greater SL of the males versus the females (1.81 m per stroke) (P < 0.05) and the similar IdC of both high-speed groups (females: 4.4%).
Conclusion: The high-speed swimmers were characterized by higher and more stable SL and IdC. The principal gender effect was greater SL in the males than in the females.
1CETAPS Laboratory, University of Rouen, Faculty of Sports Sciences, Rouen, FRANCE; and 2Laboratory of Physio-Pathology of Exercise and Handicap, Faculty of Medicine, Saint Etienne, FRANCE
Address for correspondence: Ludovic Seifert, Ph.D., Université de Rouen, Faculté des Sciences du Sport, CETAPS, Bld Siegfried, 76821 Mont Saint Aignan Cedex, France; E-mail: firstname.lastname@example.org.
Submitted for publication October 2006.
Accepted for publication May 2007.