Investigation Two Type of Absolute and Coordination Variability of Upper Limb Joints through Learning

Objective: Theories are in paradox in relation to the variability pattern with being skilled. Then this research has investigated two types of absolute and coordination variability during basketball free throw learning, with isolating mechanical and dynamical degrees of freedom. Methods: Twenty self-declared participants were randomly assigned into two groups: physical practice and control. Experimental group practiced in 12 sessions of 50 trials. Absolute variability was measured by root mean square error and coordination variability was assessed using vector coding. Result: The physical practice group was significantly better than control group in accuracy scores. Results in relation to the absolute variability revealed, only in the ankle joint, physical practice and control groups are different (P=0.037, F=5.07) and the pattern of changes supported Bernstein's theory. In the case of coordination variability, there was no difference between the two groups in any of the joints coupling. But the wrist-elbow pattern of changes in physical practice group was in accordance with the theory of dynamic systems. Conclusion:  Overall, it seems that wrist movement and wrist-elbow coordination are very important in free throw shooting skill. Also, the findings of this study showed that it is necessary to isolate mechanical and dynamical degrees of freedom in the measuring and discussing the Theories regarding the movement variability