Does floatation influence breaststroke technique?

This study is aimed at examining the relationships between floatation parameters, assessed by field tests and the stroking characteristics of breaststroke swimmers. The floatation parameters were evaluated for 23 males and 23 females by the hydrostatic lift test, the sinking force acting at the ankle test and the maximal glide length after a push-off from the pool wall test. The swimmers performed two trials at submaximal and sprint pace, and then, from the data given by a PC-video velocity system, the duration and velocity of their propulsive, recovery and glide phases were analyzed. In the female group and at slow pace, glide duration is correlated with hydrostatic lift (r = .62) and with maximal glide length (r = .44); mean glide velocity is correlated with hydrostatic lift (r = .73). In the male group and at slow pace, the sinking force was correlated with the glide phase (r = -0.66) and with the mean glide velocity (r = -0.78). At sprint velocity, the hydrostatic lift is correlated with the glide phase in the female group (r = .52). Floatation parameters have an impact on the gliding phase of the breaststroke cycle.

Inter-limb coordination in swimming: effect of speed and skill level.

The aim of this study was to examine the effects of swimming speed and skill level on inter-limb coordination and its intra-cyclic variability. The elbow-knee continuous relative phase (CRP) was used as the order parameter to analyze upper-lower limbs coupling during a complete breaststroke cycle. Twelve recreational and 12 competitive female swimmers swam 25m at a slow speed and 25m at maximal speed. Underwater and aerial side views were mixed and genlocked with an underwater frontal view. The angle, angular velocity, and phase were calculated for the knee and elbow by digitizing body marks on the side view. Three cycles were analyzed, filtered, averaged, and normalized in percentage of the total cycle duration. The competitive swimmers showed greater intra-cyclic CRP variability, indicating a combination of intermediate phase and in-phase knee-elbow coupling within a cycle. This characteristic was more marked at slow speed because more time was spent in the glide period of the stroke cycle, with the body completely extended. Conversely, because they spent less time in the glide, the recreational swimmers showed lower intra-cyclic CRP variability (which is mostly in the in-phase coordination mode), resulting in superposition of contradictory actions (propulsion of one limb during the recovery of the other limb).

Arm-leg coordination in recreational and competitive breaststroke swimmers.

The aims of this study were to assess the durations of the different arm and leg stroke phases (propulsion, glide, and recovery) and the temporal arm-leg gaps between 12 competitive and 12 recreational breaststroke swimmers. The mean ages and best times for a 50-m breaststroke were, respectively, (recreational: 16.9+/-1.6 y; 49.55+/-3.38 s; competitive: 16.2+/-1.5 y; 33.85+/-1.96 s). Each swimmer was required to swim 2 x 25-m breaststroke at two different paces (slow and sprint) while being videotaped by two underwater cameras (frontal and lateral views). At the same given speed, recreational swimmers used no glide phase which increased the relative contribution of their recovery and propulsive phases. This was mainly caused by the superposition of their leg extension and the second part of their arm recovery, indicating a technique with no glide time between the arm recovery and the leg extension. In terms of phase duration, the recreational swimmers spent more time in arm recovery and in propulsive phases. Furthermore, it was observed that for a comparable increase of swimming speed (recreational: 23.3%, competitive: 22.6%), competitors switched from a glide to an overlapped coordination while recreational swimmers adopted an overlapped technique whatever the swimming speed. As a result, the relative time spent in propulsive phases did not change in the recreational group, but increased by 27.2% in the competitive one. In a swimming developmental program, particular emphasis should be put on arm-leg coordination drills, when considering the breaststroke.