The Reactive Strength Method
by Nizar Abu-Hamdeh
The reactive method, also called "plyometric", "shock" or "hit" method (Tschiene, 1976), is an effective means for the development of explosive muscle strength (Verkhoshansky, 1963, 1968).
As is known, in reactive movements, as for example sprinting, cutting or running, the stretch-shorten-cycle occurs. During this action, there is a sharp eccentric stretch, followed by a concentric contraction which uses the effect of pe-activation, the stored elastic energy and the effect of reflex innervation of the preceding phase. For example, when sprinting, the ground contact time of the feet is only one tenth of a second. 50% of this time, 0.05 seconds, is needed to absorb the landing. During the remaining 0.05 seconds, the kinetic energy stored in the tendons, ligaments and muscles as a result of the forceful stopping action, are used for push off. This is a very explosive movement. Crucial for the effect of the explosive concentric effort is the muscle's cross section and it's composition, and the elasticity and innervation behaviour of the muscles, tendons and ligaments. The elasticity and innervation behaviour is also referred to as reactive tension ability, which is the fundament of reactive strength. Reactive strength can be seen as a form of speed strength; However, sport scientists define it as an independant motor ability.
Definition: Reactive strength is the eccentric-concentric speed strength with the shortest possible (<200ms) interconnection of both contraction regimes, displayed during the stretch-shorten cycle.
The method for the development of reactive strength has several characteristics:
- During the execution of the exercise, the concentric effort must be as explosive as possible despite of the eccentric stress.
- Short stopping and fast transition (<200ms). Therefore it is necessary to adapt loads or drop heights in a manner that the transition is performed as fast and as forceful as possible.
- The eccentric stress must be caught by the musculature, and not by the passive movement apparatus. That's why a preliminary training regime is necessary before advancing into reactive strength training.
The most important effects of reactive strength training are:
- High recruitment of muscle fiber, especially of the fast twich muscle fibers of type IIb.
- Improvement of the reactive tension ability (stiffness)
- Improved speed of the transition phase in the stretch-shorten-cycle, and thus faster and more explosive execution of the skill.
- Training of special innervation patterns needed for the optimization of explosive effort.
The reactive strength training method must be carefully integrated into the athletes training regime to avoid overuse injury and overtraining. The progression of the training loads must be gradual. An example progression for reactive strength training for the development of leg extension explosiveness is starting with double legged jumps with submaximal intensity, and advancing to vertical jumps over hurdles with height progression and shorter ground contact time. After a period of time, jumps with minimal ground contact times and for maximal heights may be integrated. Jumps may then be executed also with additional loads in the form of weighted vests, dumbbells or barbells. The ultimate progression is the depth jump method.
Here is a sample program showing how the reactive strength method might be put into a training program for an athlete who did not use the method before. I designed it for a basketball player in the offseason who was new to this method, he gained 8 inches in jump height in combination with a strength training program. It is only presented to show which exercises can be used and how the progression should be done. It is not meant for use since it is not individualized and because it is not shown in combination with other training methods.
