Purpose:
The aim of this study was to examine the dependencies between support scull kinematics and body stability in the vertical position.

Methods:
The study involved 16 synchronized swimmers. Twelve markers were placed on the pubic symphysis, head, middle fingers, and transverse axes of upper limb joints. Support scull trials were recorded at 50 fps by cameras placed in watertight housings. Calculated measures included: excursion of the sculling movement; flexion and extension angle of the elbow and wrist joints; adduction and abduction angle of the shoulder joint; adduction and abduction angle of the forearm to/from the trunk; ranges of movement of the wrist, elbow, and shoulder joints; range of movement of forearm adduction towards the trunk; and the range of movement of shoulder adduction towards the trunk.

Results:
The length of the trajectory taken by the marker on the pubic symphysis was longer if the range of movement of the wrist joint was larger. The movement of the body in the right-left and upwards-downwards direction increased together with a greater range of movement of the wrist joint. It was also found that a greater sculling angle produced greater body displacement in the forwards-backwards direction. The head marker was characterized by a significantly larger range of displacement in the forwards-backwards and right-left directions than the pubic symphysis.

Conclusions:
The findings indicate that the ability to maintain body stability in the vertical position is associated with the range of movement of the radial wrist joint, angle of forearm adduction, and a newly-introduced measure – sculling angle.