Dissimilarity between Wrist Trajectories in Basketball Dribbling: Hypothetical Differences Not Available to the Human Eye.

Previous research identified the stability of wrist position as a performance indicator in a static basketball dribbling task performance under different experimental conditions since professionals displayed higher stability values than amateurs. We hypothesized that the trajectories of this cyclical task may be different between amateurs and professionals under downward peripheral vision occlusion and auditory occlusion. A modified version of the Procrustes analysis was used to quantify the dissimilarity between wrist trajectories along time. Results showed that peripheral vision occlusion caused dissimilarity in amateurs' dribbling trajectories almost four times larger than professionals'; however, auditory occlusion did not affect neither amateur nor professionals' performance. There were no cumulative effects on performance when the individual was submitted to both occlusions simultaneously.

The role of variability in the control of the basketball dribble under different perceptual setups.

When executing a sport-specific movement, athletes cannot use all perceptual resources to control their actions. The complexity of a basketball match, demands that individuals command their attention towards the context to make decisions. The dependency on the perceptual sources to control a movement should be kept to a minimum. During a match due to situational constraints, players often see themselves with impaired perceptual sources (e.g. auditory and peripheral vision occlusions). Assuming that professional basketball players are more skilled than amateurs, we analysed how both groups were affected by perceptual impairment, within and in-between groups in a dribbling task. A variability analysis (correlation dimension, approximate entropy and Lyapunov exponent) was used to evaluate how an increased variability or stability, in a specific joint movement, contributes to a better adaptive behaviour when facing perceptual impairment. Professionals showed a significantly lower variability of the wrist movements, but had a significantly higher value of variability in the shoulder horizontal movements (anterior-posterior and lateral), and also in the lateral elbow movements when their downwards peripheral vision was impaired. The increase in variability in such joint movements reflects adaptive behaviour and might be a performance factor.