A study of the individual activity of professional volleyball players: Situation assessment and sensemaking under time pressure.

The aim of this study is to understand interindividual differences in defensive behaviour in elite volleyball players facing similar game situations. This recurrent observation leads us to adopt an activity-centred ergonomic approach. Two case studies are conducted in naturalistic contexts. In the first, thirty-one professional players are observed in order to account for typical forms of behaviour in relation to certain specific sets of game situations. Two characteristic populations are distinguished. The second study uses observations and self-confrontation interviews with twelve players representative of each population in order to characterise their situation assessment. Results highlight important contrasts between the two populations, both in behaviour and in situation assessment. They suggest that one norm of activity centred on the rally-ending issue and another on the roles to be assumed, guide the specific coherency of these populations under time pressure. The identification of these norms provides a hypothesis concerning the foundations of sensemaking. Implications for training development are discussed.