A new method was recently proposed to estimate energy expenditure and metabolic power from acceleration and speed values. In the present investigation data were collected in training during the in-season period from 26 English Premier League outfield players using GPS technology. Distance covered at different speed categories and the number of acceleration and deceleration achieved were reported. By taking into account these parameters estimated energy expenditure and metabolic power were calculated. The high-intensity demands of soccer training are underestimated by traditional measurements of running speed alone, especially in central defenders, training sessions associated with less high-intensity activity and "small" small-sided games. Estimations of metabolic power better inform the coach as to the true demands of a training session or a particular drill. A detailed analysis of different drills based on metabolic power is pivotal in contemporary soccer as it enables an in depth understanding of the workload imposed on each player which consequently has practical implications for the prescription of the adequate type and amount of stimulus required during training.