Article Four

RELATIONSHIP BETWEEN TECHNIQUE, POWER, AND SPRINT BREASTSTROKE PERFORMANCE: Assessment of Breaststroke Technique by Analysis of Intracyclic Velocity Fluctuations.

L. J. D'Acquisto  Ed.D. &  D.L.Costill   Ph.D.
Trained breaststroke swimmers (females, n=10; males, n=7) participated in this investigation to examine the relationship between swimming power, intracyclic linear body velocity fluctuations and sprint breaststroke performance.  In addition, gender differences were examined in the aforementioned variables. A velocity-video system, which assesses linear body velocity fluctuations, was employed during a sprint breaststroke performance (22.86m) to measure (1) peak kick (PK) and arm pull (PA) linear body  velocity, and (2) minimum linear body velocity prior to the arm pull (MVA) and kick propulsive phase (MVK).  An isokinetic Cybex dynamometer was adapted to measure swimming power during a partially tethered breaststroke sprint effort.  The correlation between swim power and breaststroke sprinting velocity was 0.64 (p=.11) and 0.87 (p<0.05) for males and females, respectively.  The correlation between swimming power and breaststroke performance for  91.4m and 365.8m  was 0.91 and 0.86, respectively (p<0.05).  The male swimmers were more powerful and faster than the female swimmers (p<0.05).  In addition, the male swimmers covered a greater distance per stroke cycle during the sprint performance than the female swimmers, 1.56+0.17 vs. 1.34+0.16 m.stk-1 (p<0.05).   Compared to females,  the male swimmers obtained a greater *PK, *MVA and *PA (*p<0.05), while no difference was found for MVK.  The correlation between PK, PA, MVA and breaststroke sprint velocity was  0.74*, 0.91* and 0.80*, respectively (*p<0.05).  This study illustrated that the ability to effectively generate power during a partially tethered sprint was an important predictor of both sprint and endurance breaststroke performance.   In addition, the better breaststroke sprinters were characterized by their ability to obtain a higher peak linear body  velocity  during the arm pull and kick propulsive phases.  Minimizing the drop in linear velocity before the propulsive phase of the arm pull was a common characteristic among the more successful  breaststroke swimmers.  This suggests a better streamlined body position and/or timing between the completion of the kick and start of the propulsive phase of the arm pull.  This study has illustrated the application of a less complicated system for analysis of swimming stroke mechanics.