Previous research has shown how dynamical systems theory provides a relevant framework for investigating decision-making behavior in sport. The aim of this study was to adopt concepts and tools from nonlinear dynamics in examining effects of boxer-target distance and perceived punching efficiency on emergent decision-making during a typical practice task in boxing. Results revealed the existence of critical values of scaled distances between boxers and targets for first time appearance and disappearance of a diverse range of boxing actions including jabs, hooks and uppercuts. Reasons for the diversity of actions were twofold: i) abrupt (qualitative) changes in the number of the possible punches, i.e. motor solutions to the hitting task; and ii), fine modification of the probabilities of selecting specific striking patterns. Boxers were able to exploit the emerging perception of strikeability, leading to a changing diversity of selected actions and a cascade of abrupt changes in the perceptual-motor work space of the task. Perceived efficiency of a punching action by the participants also changed as a function of the scaled distance to a target and was correlated with the probability of occurrence of specific boxing actions. Accordingly, scaled distance-dependent perceived efficiency seems an important perceptual constraint in the training task of punching a heavy bag in boxers.

• During the practicing with static (i.e. non moving) heavy bags novice boxers' perceptual-action system is sensitive to the scaled distance and efficiency informational constraints. These interdependent constraints shape the action behaviour of the novice boxers;

• During heavy bag practice novice boxers are subject to a kind of discovery learning by exploring the efficiency of their motor repertoire when changing the performer - target distances;

• The region close to D = 0.6 maximizes the flexibility of switching among different types of punching actions and is optimal for practicing the temporal couplings between all types of boxing actions;

• Strategic positioning among boxers spontaneously emerges under the pressure of the key constraints revealed in these research. Applying practice strategy that emphasizes learning in which trainees would themselves explore, discover and thus adapt to the information - movement demands of diverse sparring situations is thus of great importance.