Plyometrics, also known as plyos, are exercises in which muscles exert maximum force in short intervals of time, and activating a rapid stretch-shortening cycle. While commonly associated with jumping, plyometrics can include explosive upper-body movements, such as plyometric push-ups and switch-ups, with the goal of increasing muscular power (speed-strength).
This training focuses on learning to move from a muscle extension to a contraction in a rapid or "explosive" manner, such as in specialized repeated jumping. The amortization phase (transition from extension to contraction) must be very brief, as a slow transition will not fully release elastic energy stored in eccentric phase, and instead some stored energy leaks away as heat. For example, a person lands after jumping and absorbs any shock. The thigh (quadricep) muscles extend during this process. The amortization phase begins which involves the reorientating and channeling of the stored muscular energy from the landing and shock absorption, into the preparatory and preloading action for the jump. This energy is then subsequently channeled into the main jumping action which involves the thigh muscles contracting. In plyometrics, it is important that the amortization phase is completed as quickly as possible in order to maximise the potential to bridge between the landing and jumping actions and transfer energy between them. Describing the changes as occurring between phases of muscle extension and contraction is a simplification of the overall process which is more complex and involves a system of simultaneously occurring and interconnected muscle extensions and contractions.
Stretch shortening cycle training loads tendons elastically and when done properly, it can yield benefits including improved landing mechanics, force absorption, joint stability and greater force and power output, with transferability to many athletic activities, such as sprinting, where similar repetitive movements are required. Progressive plyometric training can also help to reduce the chances of injury, especially to the lower leg, ankle and foot.
Plyometrics are frequently used by athletes, especially martial artists, sprinters and high jumpers, to improve performance, and are used in the general fitness field to a lesser degree.
Overview Plyometrics include explosive exercises to activate the quick response and elastic properties of the major muscles. It was initially adopted by Soviet Olympians in the 1950s, and then by sportspeople worldwide. Sports using plyometrics include basketball, tennis, badminton, squash and volleyball as well as the various codes of football. The term "plyometrics" was coined by Fred Wilt after watching Soviet athletes prepare for their events in track and field.Wilt, Fred & Yessis, Michael. Soviet Theory, Technique and Training for Running and Hurdling. Vol 1. Championship Books, 1984. He began a collaboration with trainer Michael Yessis to promote plyometrics.
Since its introduction in the early 1980s, two forms of plyometrics have evolved. In the original version, created by Soviet scientist Yuri Verkhoshansky, it was defined as the shock method. In this, the athlete would drop down from a height and experience a "shock" upon landing. This in turn would bring about a forced eccentric contraction which was then immediately switched to a concentric contraction as the athlete jumped upward. The landing and takeoff were executed in an extremely short period of time, in the range of 0.1–0.2 second. Explosive plyometrics describes the approach originally created by Verkhoshansky. He experimented with many different exercises, but the depth jump appeared to be the best for duplicating the forces in the landing and takeoff.
The second version of plyometrics, seen to a greater extent in the United States, involves any form of jump regardless of execution time.
Etymology The term plyometric is a combination of Greek words πλείων (pleíōn), which means "more", and μέτρον (métron) "measure". Fred Wilt admits that it is not a very good term, but it was the best he could come up with. The spelling that would match the Greek origin is pliometrics. Several imaginary Greek words that would explain the y have been cited.
History
Fred Wilt, a former US Olympic long-distance runner, is credited with coining the term plyometrics after watching the Soviets execute jumps in their warm-ups prior to their event in track and field. He could not understand why the Soviets were doing all of these jumps while the Americans were doing multiple static stretches, but he firmly believed it was one of the reasons why they were so successful in many events. From its beginnings in the early 1980s, the term plyometrics gained greater popularity and is now well established. When Fred Wilt learned of the work being done by Michael Yessis in the field of Soviet training methods, they quickly teamed up to help disseminate information on plyometrics.
In collaboration with Yessis who visited and worked with VerkhoshanskyMcCadam, K., "Russian Training Legend: Dr. Yuri Verkhoshansky." Retrieved online April 22, 2012 from http://www.pushtheground.com/2011/06/russian-traning-legend-dr-yuri.html in the Soviet Union in the early 1980s, plyometrics was gradually disseminated in the US. Yessis brought this information on plyometrics back to the US and in the following years was able to create even more ways of using this method to train and improve explosive power.
Plyometrics (the shock method) was created by Yuri Verkhoshansky in the late 1960s, early 1970s. Since then, the shock method of plyometrics is still being practiced for improvement of athletic performance by what appears to be a relatively limited number of athletes. These athletes still do depth jumps, the key exercise in the shock method, according to the guidelines established by Verkhoshansky.
Most athletes execute simple and complex jumps and call them plyometrics rather than jump training as it was called in the past. This includes the depth jump which was executed in ways different from what was recommended by Verkhoshansky. This form of jump training is very popular but plyometrics is a buzzword for all types of jumps, regardless of how long it takes to execute the jump. Its use is so pervasive that it is even possible to find push-ups described as being plyometric.
Due to the wide use and appeal of the term plyometrics, the true meaning of plyometrics as developed by Verkhoshansky has for the most part been forgotten. Verkhoshansky was well known and respected worldwide in both the scientific and in the coaching arenas. He was relatively unknown in the United States except for some of his articles that were translated and published in the Soviet Sports Review, later called the Fitness and Sports Review International.
In addition to creating the shock method, Verkhoshansky is credited with developing the stretch-shortening concept of muscle contractions and the development of specialized (dynamic correspondence) strength exercises. Plyometrics, or more specifically the shock method, is considered a form of specialized strength development.
Before undertaking plyometric training, it is necessary to distinguish jumps that are commonly called plyometric and true plyometric jumps as exemplified in the depth jump which is illustrative of the shock method. Since its inception in the former Soviet Union as the shock method, there have been other forms of the plyometric exercises created by Yessis that do not involve jump exercises. For details and illustrations of these exercises see "Explosive Running" and "Explosive Plyometrics". These exercises involve the stretch-shorten concept that underlies the shock method.
Exercises
Lower-body Squat jump (jumping squat, jump squat): combination of jump (not to be confused with tuck jump) and squat. Squat down then jump off the ground as high as possible, with extended and vertical legs. Tuck jump (tucked jump, tucked knee jump): with feet shoulder width apart, jump, tuck the legs in, extend them, and land. Tuck squat jump: combination of tuck jump and squat jump. Squat down, jump, bring knees up before landing again. Lateral jump: from a standing position, jump side to side. Single-leg hops / bounds: explosively jumping forward or laterally using one leg at a time, focusing on balance, power, and landing control. Alternate leg bounding: run with long strides, placing emphasis on hang time. Box jumps: jump onto and off of a large box 45 cm or higher. Vertical depth jump: starting from the top of a box, jump down and back up as fast as possible. Broad jump (long jump). Pike jump. Frog jumps: squat, place your hands on the floor, and jump forward explosively as far as possible, landing softly and immediately preparing for the next jump. Straddle jump (similar to split jumps used by dancers, gymnasts and figure skaters). Lunge jump
Upper-body Plyometric push-up (plyo push-up): perform a push up, but exert enough upward force to lift the hands and body off the ground. Medicine ball chest pass: hold a medicine ball at chest level and explosively throw it forward using both hands, extending the arms rapidly as in a basketball chest pass. Medicine ball cross slams (one-arm diagonal slam): Hold the medicine ball in one hand, raise it overhead on one side, then explosively rotate the torso and hips to slam it diagonally across the body toward the ground. Medicine ball slams: lift the medicine ball overhead and forcefully slam it straight down to the ground, engaging the core, shoulders, and arms. Switch-ups (explosive pull-up/chin-up variations): An advanced plyometric exercise in which one uses alternating grips on a bar to perform a pull-up / chin-up, and at the top, explosively switches the grip or hand position before lowering. This heavily engages the shoulders, but is regarded comparatively safer to a muscle-up.
Full-body Power skipping: On each skip, lift the upper leg as high as possible while driving the opposite arm upward to maximize stride height and explosive leg drive. Burpee jumps: from a standing position, drop into a squat, kick your feet back into a plank, perform a push-up, return to squat, and explosively jump upward. Due to pauses and multiple phases that reduce SCS effectiveness, burpees are not considered pure plyometric exercises. They contribute more to muscular endurance and general conditioning than to maximal force or power development. Burpee broad jumps: An advanced variation of the standard burpee, closer to a pure plyometric because it emphasizes rapid SSC use. It's like a standard burpee, but instead of jumping straight up, explosively leap forward as far as possible, land softly and immediately prepare for the next repetition. Bounding: run with exaggerated, powerful strides, pushing off each leg forcefully and focus to maximize both forward distance and hang time. Jump rope: Repeatedly skipping over a rope with knees slightly bent, engages the stretch-shortening cycle of leg muscles with each jump, making it a form of low intensity plyometrics.
Method In the depth jumps, the athlete experiences a shock on landing in which the hip, knee, and ankle extensor muscles undergo a powerful eccentric contraction. For the muscles to respond explosively, the eccentric contraction is then quickly switched to the isometric (when the downward movement stops) and then the concentric contraction, in a minimum amount of time. This allows the athlete to jump upward as high as possible.
In the eccentric contraction, the muscles are involuntarily lengthened, while in the concentric contraction, the muscles are shortened after being tensed. Most of the stretching and shortening takes place in the tendons that attach to the muscles involved rather than in the muscles.