said principle said principle in physical rehabilitation and sports training, the said principle asserts that the human body adapts specifically to imposed demands. it demonstrates that, given stressors on the human system, whether biomechanical or neurological, there will be a specific adaptation to imposed demands (said). for example, by only doing pull-ups on the same regular pull-up bar, the body becomes adapted to this specific physical demand, but not necessarily to other climbing patterns or environments. in 1958, berkeley professor of physical education franklin m. henry proposed the "specificity hypothesis of motor learning". progression start basic/simple then move to advance/complex slow to fast low force to high force short distance to long distance bilaterally to unilaterally gradually use the overload principle.