The complexity of dynamical systems (spanning brain, body and environment) can yield complex adaptive behaviors from non-linear interactions of individuals in space and time. A lack of reliable instruments to assess these varying behaviors results in inferences of how changes in behavior occurred over an extended period of time rather than being based on direct scientific measures. The aim of this study was to develop a scale of complexity and perceptual-cognitive skills\u27 assessment in the sport soccer and to evaluate structural and criterion reliability. Based on the embodied cognition literature, the construct of this scale was identified with three dimensions to assess perceptual-cognitive performance of players when acting within different levels of complex team synergies. A sample of 10 soccer coaches - group A (n = 5 coaches; M = 24 yrs professional coaching experience) and group B (n = 5 coaches; M = 1 year of amateur coaching experience) were recruited to participate in the study. A total of 100 clips of 10 previously recorded soccer matches were analyzed in two assessment periods with one month between the end of the first assessment and the beginning of the second. This resulted in a combined total of 1000 measures used for the study. The results demonstrated that high skilled coaches were more reliable in the complexity dimension (r = 0.87) and also in the decision making dimension (r = 0.79) than low qualified coaches (r = 0.79) and (r = 0.71) respectively; and the complexity dimension was more stable across trials between professional and amateur coaches in the first data collection i (r = 0.79) and second data collection (r = 0 .73) than the decision making dimension (r = 0.50) and (r = 0.43) respectively. These findings indicate that this scale is reliable across applications and at different times with high and low qualified coaches. The use of the scale may be useful for identifying elements of emerging complexity at the team-fractal-player level; determine a perceptual-cognitive profile in athletes; and to better understand complex tactical dynamics in soccer
