Effects of a high-intensity swim test on kinematic parameters in high-level athletes.

The present study aimed to investigate the effects of a high-intensity swim test among top-level swimmers on (i) the spatial and temporal parameters of both the stroke and the 3-D fingertip pattern and (ii) the mechanical, muscular, and physiological parameters. Ten male international swimmers performed a 4 x 50 m swim at maximal intensity. Isometric arm flexion force with the elbow at 90 degrees (F90 degrees ), EMG signals of right musculus biceps brachii and triceps brachii and blood lactate concentrations were recorded before and after the swim test. Kinematic stroke (stroke length, rate, and velocity) and spatiotemporal parameters of the fingertip trajectory were measured by two underwater cameras during the first and last 50 m swims. After the swim test, F90 degrees and mean power frequencies of the EMG decreased significantly when blood lactate concentration increased significantly, attesting the reaching of fatigue. From the first to the last 50 m, stroke rate, stroke velocity, and temporal parameters of the fingertip trajectory exhibited significant increases although stroke length and spatial fingertip trajectory remained unchanged. General and individual adaptations were observed among the top-level swimmers studied. The present findings could be useful for coaches in evaluating fatigue effects on the technical parameters of swimming.