Kinetics, kinematics, and performance modeling of two arm swing techniques in the swimming kick-start.

This experimental study investigated the effect of two arm swing techniques on kinematic and kinetic variables during the swimming kick-start. Twelve elite male swimmers performed starts using forward and butterfly arm swing techniques. Kinematic and kinetic data were collected using a Kistler Performance Analysis System. Data were analyzed for variables calculated from ground reaction force (GRF) and block, above the water, and underwater performance. The results revealed that work, power, and most of the force parameters measured higher values for the butterfly arm swing technique (p < 0.05). The butterfly arm swing was also advantageous regarding resultant underwater and vertical take-off velocities (p < 0.05). The butterfly arm swing technique demonstrated a significant correlation (p < 0.05) between the 15 m swimming time trial and additional parameters, including take-off horizontal velocity, power, force on the block, entry distance, and performance at 5, 7.5, and 10 m of swimming. Regression analysis indicated the combination of different predictors of the time to 15 m, including some GRF metrics, and above the water and underwater parameters for both types of arm swing. The butterfly arm swing produced a significantly shorter start time over the distance from 7.5 m to 15 m than the forward arm swing (p < 0.05). However, this is not necessarily related to the early phase of the start because no significant differences between analyzed dives were found at the 5 m time (p = 0.056).