In physical therapy and sports coaching, the SAID principle asserts that the human body adapts specifically to imposed demands. In other words, given stressors on the human system, whether biomechanical or neurological, there will be a Specific Adaptation to Imposed Demands (SAID).
In 1958, Berkeley Professor of Physical Education Franklin M. Henry proposed the "Specificity Hypothesis of Motor Learning".
The SAID principle is often cited today by Strength & Conditioning Coaches as well as Athletic Trainers to remind athletes that all training is specific to a particular task. In other words, specific skills or training may not easily generalize or transfer to distinct activities, either in terms of physical or intellectual training activities.