Abstract: It is the similarity and difference in energetics in exercises that determines applying the training theory from one sport to others.Both similarity and difference exist in energetics of different exercises.The exponential correlation between relative oxygen contribution and du- ration of maximal exercise with involvement of large muscles is independent of exercise model, given the involved muscular of similar training level.Resulting from different involvement of muscular in exercises, the maximal lactate steady state varies in different exercises.Maximal lactate steady state, together with method of step test, should be considered when giving a fixed value to the lactate threshold.The introduction of energy cost made it possible to com- pare the efficiency of energy utilization between different exercises.Energy cost in different ex- ercises could provide energetic background for competitive sports and physical activities.