In physical rehabilitation and sports training, 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".
1. start basic/simple then move to advance/complex
2. slow to fast
3. low force to high force
4. short distance to long distance
5. bilaterally to unilaterally
6. gradually use the Overload Principle