Biomechanics of diving: the influence of the swimming speed on the kinematics of lower limbs of professional divers

The aim of this study is to evaluate the influence of the swimming speed during diving on the biomechanical parameters describing the movement of selected measurement points of the lower limb in professional divers. Methods: The study involved a group of 4 professional divers whose movement was recorded during underwater swimming at slow (approx. 0.4 m · s–1), medium (approx. 0.5 m · s–1), and fast (approx. 0.8 m · s–1) pace. Results: During swimming at medium speed, the divers made a smaller displacement (along the axes Y) of the midpoint of fin than during swimming at fast speed. The range of motion in the ankle joint increased in fast speed in comparison with low and medium swimming speed. The same relationship was noted for the obtained velocity and angular acceleration in the hip, knee and ankle joints. The authors observed that during swimming at slow pace the divers choose movement ensuring high swimming comfort while the efficiency of motion is a secondary factor. On the other hand, during swimming at higher pace, the applied movement pattern ensures far greater efficiency rather than swimming comfort. Conclusion: The conducted analysis showed that divers adjust the movement of their lower limbs to the swimming pace.