The need for ever increasing achievements in athletic performance is pushing the acquisition costs and salaries of top performers to unprecedented heights. Individual talent, good physical condition and relentless training, however, do not by themselves guarantee success of the team effort. Team performance is determined by game strategy and team coordination. Ideally, during a game, the team coach should be able to gauge the instantaneous physical condition and performance reserves of each player on the team and direct game strategy accordingly. Our experimental setup explores the feasibility of objectively estimating, in real time, the intensity of physical activity and the physiological performance reserves of each and every player on the team during a game of soccer.