NON-PROPULSIVE PHASE IS THE WEAK SPOT IN BREASTSTROKE SWIMMING
Takagi, H., Sugimoto, S., Nishijima, N., & Wilson, B. (2004). Differences in stroke phases, arm-leg coordination and velocity fluctuation due to event, gender and performance level in breaststroke. Sports Biomechanics, 3, 15-27.
This study analyzed stroke phases, arm-leg coordination, and trunk motion fluctuation during elite male and female 50, 100 and 200-m breaststroke events at the 9th FINA World Swimming Championships at Fukuoka 2001. Four phases of the arm stroke and three phases of the leg kick as well as phases of simultaneous arm and leg propulsion and recovery were identified from video of swimmers' motions below the surface. The duration of each phase was expressed as a proportion of the whole stroke cycle. Three measures of the arm-leg coordination, percent simultaneous arm-leg recovery time, percent arm lag time, and percent simultaneous arm-leg propulsion time were calculated. Mean mid-pool swimming hip velocity, stroke rate, and stroke length were also calculated. In addition, the intra-cycle hip velocity of the swimmers was obtained by cinematographic analysis.
Stroke rate decreased and stroke length increased significantly as event distance increased. For the arm-leg coordination, the percent arm lag time, percent simultaneous arm-leg propulsion time, and percent simultaneous arm-leg recovery time indicated significant differences between events, genders, and performance levels. In particular, for increasing event distance and for the higher performing swimmer the lower the percent simultaneous arm-leg propulsion time the higher was the percent simultaneous arm-leg recovery time. In addition, the range of the intra-cycle hip velocity fluctuation in the lower performing swimmers was greater than in the higher performers.
Implication. The non-propulsive phase appears to be a key factor for better breaststroke performance. Breaststroke swimmers should avoid rapid deceleration during the non-propulsive phase by adopting a low resistance posture and reducing the lag time between propulsive phases of the stroke.
Return to Table of Contents for Biomechanics of Swimming.