EVALUATION OF STRENGTH TRAINING CONCEPTS
Sale, D., & MacDougall, D. (1981). Specificity in strength training: A review for the coach and athlete. Canadian Journal of Applied Sport Sciences, 6, 87-92.
Two theories were evaluated in light of the published literature.
- Strength training exercises should simulate the sport movement as closely as possible in terms of movement pattern, movement velocity, type of contraction, and force of contraction.
- It is only necessary to train muscle groups. Increases in strength can be re-educated into a sports action.
- A large part of strength training is skill acquisition.
- Strength gained from eccentric/concentric contractions is only partially transferred to an isometric contraction.
- Adaptation may even be purely specific to the joint angle at which training occurs.
Implication. There is little likelihood of carry-over value of strength-training effects derived from simple activities to "actual applied-strength" in complex activities.
- In some studies fast training has produced almost the same results as low-velocity training while others have shown the velocity to be specific, that is, slow training improves slow movements and fast training improves fast movements.
- Slow velocity training enlarges both types of muscle fibers.
- Greater hypertrophy occurs in fast-twitch fibers, probably because they are more reactive.
- Provided the degree of effort is maximal, the motor unit activation is similar regardless of the contraction velocity.
- Fast-twitch fibers are activated even in isometric contractions.
- Fast-twitch fibers are designed to contribute to force, regardless of velocity.
- Slow-twitch fibers contribute to rapid movement (0.1 sec or less) strength.
- The specificity of velocity in strength is related to the organization of movements by the brain rather than to selective recruitment of motor unit types.
- Slow-velocity training may be necessary to stimulate maximum adaptation within the muscle [and therefore, would be appropriate for therapy programs].
- Muscle growth is related to the amount of tension within the muscle.
- Low loads, high repetitions do not produce muscle enlargement unless the original starting level was particularly poor.
- As the velocity of contraction increases, the force that can be developed decreases despite maximal effort.
Implication. Mix fast movements to train the nervous system (movement patterns) and slow to train the muscle structures. The difficulty is to have the training movement patterns replicate those of the contest activity.
Type of Contraction
- Muscles are strongest when contracting eccentrically and weakest when performing concentrically. The reason for the greater eccentric strength resides within the contractile mechanism of the muscle, NOT an energy system.
- Emphasizing the same type of contraction in training as occurs in a competitive performance could facilitate event-specific neural adaptation to occur. [However, in practical terms, this is impossible.]
- It might be advantageous to employ eccentric training because its overload will stimulate structural adaptation [but whether that is transferable to an event depends upon other factors].
- Eccentric training is the primary stimulus in plyometric or "rebound" training.
- Concentric force is increased when preceded by high velocity eccentric contractions.
Implication. The type of contraction must duplicate that of an event to have carry-over value. To stimulate muscle growth, eccentric contractions have a greater potential for effect than concentric contractions.
- Low repetitions (1-3) produce different adaptations to moderate repetitions (8-10).
- Beginners' training does not have to be as specific as that for elite athletes. [The problem is can strength training realistically be made to be specific for an activity?]
Implication. The force of the training contraction should match that of the intended event otherwise a different/inappropriate form of adaptation will occur.
SUMMARY AND IMPLICATIONS
- Strength training should be as specific as possible. The movement pattern and contraction speed, type, and force should replicate the intended activity. Any departure from one of these factors will result in inappropriate adaptations.
- High-velocity sports may need supplemental low-velocity training to induce maximal adaptation within the muscles.
- Supplementary maximal training may be beneficial because it stimulates maximal adaptation. However, that adaptation should be achieved before serious technique work begins.
- Non-specific training has a high probability of being counter-productive.
- There is no evidence to support the "re-education of strength gains" hypothesis.
Return to Table of Contents for this issue.