Spatial consistency of circle on the pedagogic pommel horse: influence of expertise.

Gymnastics is a closed-skill sport, and the repeatability of a specific technique is accepted as a valuable indicator of a performer's level of expertise. The circle movement, defined as a gyrating movement in the horizontal plane, is a key component of all contemporary pommel horse exercises. The aims of this study were to determine the spatial consistency of the circle movement and to assess the influence of expertise on the repeatability of this skill performed on the pedagogic pommel horse. Six expert gymnasts and six nonexperts performed 10 circles on this apparatus. A 3-dimensional analysis system recorded the trajectories of 6 markers fixed on the right and left ankles, hips, and shoulders. The spatiotemporal consistency was assessed by the SD of the marker trajectories during the circle sequence. The results showed that the shoulder and trajectories were more consistent than the ankle trajectory (P < 0.05); the marker trajectories were less consistent in the sagittal plane (P < 0.05); and the expert gymnasts showed better repeatability of the ankle trajectory than the nonexpert gymnasts did (P < 0.05). In this context, the use of the SD of the ankle trajectory during the circle sequence could be an interesting tool for trainers to quantify objectively the positional errors of the legs during circular swings and to measure the improvement in movements after specific training.