Postural stability and skilled performance--a study on top-level and naive rifle shooters.

Posture control during aiming over a period of 7.5 s preceding the shot was studied among national top-level rifle shooters as well as among national level shooters and amateurs familiar with rifle shooting. Movement of the center of forces (COF) was analyzed in terms of the speed and amplitude of the movement. These calculations were carried out in 1.5 s windows, the first window beginning 7.5 s and ending at 6.0 s prior the shot. The last window ended at the trigger pull. Posture control data differentiated the studied groups according to their level in competitive shooting. The male top-level shooters could stabilize their posture significantly better than female top-level or male national level shooters, who were, in turn, much more stable than naive shooters. The experienced shooters were able to stabilize their posture even better during the last seconds preceding the shot, whereas in naive shooters there were no significant differences when the successive windows were compared with each other. When a comparison was made between the best and worst 20 shots of each subject, a significant difference in balance parameters was only observed among the naive shooters, who showed more pronounced movement of the COF in the less successful trials. Among the highly trained top-level shooters a miss in whole-body posture stabilization apparently seldom is a reason for a poor result.