Specificity

Specificity is the training principle of matching the demands placed on a client to the intended result, targeting particular muscles, energy systems, movement speeds, movement patterns or muscle actions.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 408.} It’s often used interchangeably with SAID, specific adaptation to imposed demands: the demand determines the adaptation.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 456.}

Transfer between activities depends on how closely they match.^{3Zatsiorsky, Kraemer and Fry, Science and Practice of Strength Training, 3rd ed., p. 23.} In Zatsiorsky’s example, athletes who add 20 kg to their squat would expect a large gain in standing jump performance, a small gain in sprinting and almost none in swimming.^{3Zatsiorsky, Kraemer and Fry, Science and Practice of Strength Training, 3rd ed., p. 23.} Joint angle matters too: isometric knee extension training at a deeply bent 70 degrees raised strength about equally at all angles, while training at a straighter 130 degrees mostly helped neighboring angles.^{3Zatsiorsky, Kraemer and Fry, Science and Practice of Strength Training, 3rd ed., p. 23.}

In practice

To strengthen the legs, choose lower body exercises such as the back squat and leg press; for a volleyball player, add squats and Olympic lifts that resemble jumping.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 408.} Include at least one exercise that mimics the movement pattern of each main skill in a client’s sport.^{4Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 630.}

Across preseason, in-season and postseason, training should progress in an organized way from general work toward the sport’s specific demands.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 456.} Each part of the program should have an explainable connection to the goal; otherwise, it probably breaks the principle of specificity.^{5Israetel et al., Scientific Principles of Hypertrophy Training, p. 13.}