This study aims to investigate the intracycle velocity fluctuations（ IVF） and stroke parameters （Stroke Length and Stroke Rate） during the 200 m swimming of the breaststroke. Twenty-four competitive collegiate swimmers （females, n＝11; males, n＝13） performed with the maximum effort required to keep steady pace. Swimming performances were videotaped simultaneously using two cameras at different views（ i.e., frontal and lateral views）. Stroke cycles for each 50 m were analyzed over the 200 m swim course. IVF was employed during the breaststroke performance analysis to measure （1） the peak velocity during the kick （V Kpeak）, （2） the peak velocity during the pull （V Apeak）, （3） minimum linear body velocity before the arm pull motion （V Glide）, and （4） minimum velocity with leg recovery （V Recovery） calculated as a percentage of the mean swimming velocity. Videotaped swimming performances were analyzed to obtain the stroke rate, stroke length, and mean swimming velocity.
V Kpeak significantly decreased in the last 50 m of the course. In addition, a significant increase was observed over the same interval for V Glide. Although V Kpeak decreased, swimmers maintained the mean swimming velocity, and V Glide increased simultaneously. Thus, for a given subject, even if the mean swimming velocity remained constant, changes in IVF were observed during the 200 m swimming of the steady pace breaststroke.
It is concluded that the evaluation associated with IVF and stroke parameters provided useful and detailed race strategy and evaluation.
