The Overload Principle is the principle on which strength and endurance  development depends. It was expressed in the scientific literature by Lange, in 1919. In his paper, “ Uber Funktionelle Anpassung,” The principle states that the strength, endurance and hypertrophy of a muscle will increase only when the muscle performs for a given period of time at its maximal strength and endurance capacity, i.e., against workloads that are above those normally encountered.

One of the first experimental demonstrations of this principle in humans was done by  Hellebrant and Houltz – “ Mechanisms of muscle training in man experimental demonstration of the overload principle.” What is surprising is this study was not done until 1956. Then terms such as Underload and Progressive Resistance were used and further research of Lange’s principle added the words Systematic and Progressive to the Overload Principle.

It became clear that physical activity is not synonymous with physical training. For development to occur you need a certain level of intensity, a certain duration and a certain frequency of training and it must be systematic and progressive. This is what coaches try to do by giving you a ‘certain’ amount.

Lange unraveled a puzzle of nature because the puzzle existed. People were built before Lange, but he explained why. Once we understood the phenomenon, because someone could explain it, we were able to move onto new and different problems and become better at implementing muscular growth.

What this means to all of us is that we have a ‘principle’ associated with weight training that if we follow it, we will get stronger – always – but we must follow it. Follow the Overload Principle and manage intensity, duration and frequency; systematically and progressively to cause muscular or physiological adaptations –  a ’certain’ amount.