A study of kinesthetic after-effects on shot-put performance

The purpose of this study was to examine kinesthetic after-effects on shot-put performance. In experiment 1, involving 22 male university students, it was examined whether any kinesthetic after-effects would be evident in terms of throwing distance when shots of different weights were thrown. The results demonstrated a kinesthetic after-effect: the participants felt that it was easier to throw a standard-weight shot (4.0 kg) after throwing a heavier shot (5.45 kg), and they performed better in terms of throwing distance. However, no difference in throwing distance was evident when the standard-weight shot was thrown after throwing a lighter one (2.72 kg), although a kinesthetic after-effect was observed. In experiment 2, involving 16 male university students, it was examined whether any kinesthetic after-effect or improvement of throwing distance would result from throwing different weights of heavier shots (5.0 kg and 6.0 kg) before throwing the standard-weight shot (4.0 kg) 5 times. Kinesthetic after-effects and improvements in throwing distance were observed. However, there was no difference in the distances of the five throws corresponding to the weights of the shots. In experiment 3, involving 27 male university students, it was examined whether any kinesthetic after-effect or improvement in throwing distance would be evident when there was a difference in time interval after throwing a heavier shot (6.0 kg). Although kinesthetic after-effects and improvements in throwing distance were observed, there was no difference according to time interval. The above results suggest that shot-put performance would improve due to after-effects caused by throwing heavier shots. This improvement in performance might be explained by ‘post-activation potentiation’ and ‘perceptional illusion’ resulting from throwing heavier shots.