Strength training guidelines tend to be based on stress factors such as relative weight, repetitions, sets, rest inbetween sets, muscle action velocity and number of sessions per week. Based on the stress-strain-concept, empirical results and training experience require additional parameters related to the molecular and cellular adaptations for an effective strength training concept. In contrast to what has generally been assumed, it is notable that the individual percentage of 1-Repetition-Maximum (1 RM) is not the intensity but only a relative training load and therefore a stress factor. Intensity is referred to here as a strain factor, operationalized as the level of effort applied to a given load.