In the case of running, more force is available upon a rapid stretch, and therefore the ensuing explosion coming off the toes on the next stride is greater.īut the phase we skipped is critical. Because power is the product of force and velocity, the more force you provide to any contraction, the more power the muscles involved develop. Here, stored energy is used to increase the force of the subsequent contraction. Let’s skip to the third phase, known as the concentric phase. So in the eccentric phase of a plyometric movement, a muscle (like the calf) has stored energy.

The muscle lengthens in this phase, called the eccentric phase, and the muscles involved in resisting that lengthening movement are being “pre-loaded.” In the simple case of running, when your foot strikes the ground, your calf muscle lengthens under the load. That force could occur upon landing or when the muscle encounters a resistance (such as a medicine ball). In the first phase, the muscle is stretched when a force is exerted on it. Now that you have a grasp of the forces involved in plyometrics, here’s how it all comes together in training. Plyometrics uses this reflex by adding the force of the spindle-initiated contraction to the muscle’s subsequent contraction during an explosive movement. The nervous system responds reflexively, immediately contracting the muscle in order to protect it. When a stretch occurs rapidly, the muscle spindle senses potential danger and sends a signal to the central nervous system. Muscle spindles (located near the muscle belly/tendon tie-in) protect the muscle from damage caused by a too-strenuous stretch. There also are neurophysiological factors in plyometrics. Increased muscle force in a plyometric exercise stems from three physiological components: (1) Elastic energy in muscle tissue and tendons is stored during a rapid stretch and can be released if a contraction immediately follows that rapid stretch (2) when a muscle is stretched, the microfilaments that cause muscle contraction may be at the best length to bind and produce force during a subsequent contraction and (3) there is resistance from muscle tissue itself (a kind of “rubbery” quality of muscle) during an unstimulated stretch, and this “passive” resistance adds to the subsequent force generated. So let’s look at the science of “plyo” to show how the original concept can include core training for a tummy you will be proud to display. The focus was on keeping the time between landing and takeoff short. Improvement in performance came following a drop from height and subsequent immediate jump. But when plyometrics was developed about 50 years ago, it was described as a “shock method” of training. When Oxygen readers see the word “plyometrics,” they likely think of box jumps or “jump training” as a broad-based approach to improving power. Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members!

Explosive bicycle crunch