Overload principle: The attempt to challenge the musculoskeletal system with unaccustomed stimulation such as, but not limited to, increased weight, speed, or volume of training (number of sets or reps)
Specificity: The focused effort of exercise in a certain way such as anaerobic/aerobic, strength/endurance. S.A.I.D. Principle: Specific Adaptation to Imposed Demands.
Individual Difference: The taking into account the genetic makeup, exercise history, fiber type ratio, motivation level, and anatomical physics of the body.
Reversibility: A major decrease in strength and aerobic capacity are apparent after two weeks without exercise, and a major decrease in aerobic capacity after three weeks without exercise.
Periodization: The gradual cycling of workout parameters such as specificity, intensity, or volume to achieve a specific goal.