The first aim of the present work was to investigate movement reorganization with learning a complex motor skill, racewalking. The second aim was to bring more insight into the role of metabolic factors and perceived exertion. To do so, the first two studies analyzed the evolution of a large number of kinematic variables when participants underwent the practice sessions. At the start of each session, three instructions (i.e., biomechanical constraints) concerning the regulations and technique of racewalking were given. The results of the first study put forward a rapid evolution ofcoordination and control (Newell, 1985) that seem to reach a plateau at the fourth session out of seven in total. The second study, that investigated closely these first four sessions, revealed an important role of task constraints on movement reorganization, refuting the existence of general principles concerning the mastery of degrees of freedom (Bernstein, 1967). Furthermore, the first study showed a reduction in metabolic values and peripheral perceived exertion with practice, which were significantly correlated to the global movement reorganization. Overall, the results seem to raise an important role of peripheral sensory information on the adoption of more economical movement patterns with practice. The third study showed that after the seven learning session, participants spontaneously adopted racewalking as a new pattern in the transition test, between walking and running, for non-metabolic reasons. In conclusion, the present work proposes that the movement reorganization accompanying the learning of racewalking is oriented by task constraints on one sideand peripheral perceived exertion on the other aiming for metabolic optimization. Nevertheless, optimization of metabolic factors doesn’t seem a priority when the motor system should quickly adapt to a critical level of constraints.
