“The variability of human movement can be defined as the typical variations that are present in motor performance and are observed in several repetitions of a task.
This variability is inherent in all biological systems” (N.Stergiou).

Performing the same routines in training programs is great to some extent. The organization of training programs needs to be specific, but also provide small changes to promote adaptation, progression and stimulation. There must be some level of chaos, so that central nervous system can self-organize the movement, to achieve the goals, promoting better adaptation. The use of nonlinear tools better captures the variation in motor behavior over time, thus allowing better control of adaptations to training programmes. Healthy and highly adaptable systems depend on achieving an optimal state of variability. How do we look for optimal variability?