Alpha Progression
Specificity principle
The specificity principle states that training adaptations are shaped by the particular demands imposed during training. It is often summarized as SAID: specific adaptations to imposed demands. The muscles, movement pattern, range of motion, joint angles, contraction type, load, velocity, duration, energy-system demand, and skill practiced all influence what improves most.
Specificity does not mean that training transfers only to an identical test. Shared muscle groups, force demands, movement features, and physiological capacities can produce useful general transfer. The principle instead predicts that improvement is usually greatest when training increasingly resembles the target. A 2025 systematic review and meta-analysis found that dynamic resistance training improved the trained dynamic-strength domain more than an untrained isometric-strength test, illustrating both task-specific gains and partial transfer.
For maximal strength, practicing the target lift, technique, and relevant loading helps express force in that task. A leg press can strengthen and grow muscles used in a squat but does not teach the barbell squat’s balance and coordination. Likewise, training through one range of motion can transfer beyond that range, yet strength gains tend to reflect the positions practiced. Exercise variation can build supporting capacities, while specific practice connects them to the goal.
Velocity and duration are also specific. Heavy lifting can raise force capacity, but muscular power benefits from opportunities to produce force quickly. Easy continuous work and hard intervals can both improve endurance, though their effects differ with the intensity and work-to-rest pattern. Technique-heavy sports require practice under perceptual and decision demands that gym exercises cannot fully reproduce.
Use specificity to prioritize, not to eliminate variety. General exercises can develop muscle, capacity, and tolerance; more specific exercises rehearse the exact performance. The best balance changes with the goal and calendar: farther from a test or competition, broader work may be useful, while closer to it, exercise selection and testing should increasingly match the required task. Progress should then be judged with a measure specific enough to answer the original goal.
