Table of Contents: Chapter 1: General vs. Specialized Conditioning Chapter 2: Active vs. This way, gains in general strengh can be most effectively transfered into sport speed and power: athletes will jump higher, run faster and change directions quicker. The concept of general and specialized training is no secret, for example it was core part of the East German Training Program and has been studied and applied extensively by the soviets who were convinced of the effectiveness of these exercises. Unfortunately the concept is not practised enough especially in the US. Regarding this subject, Dr.
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Method[ edit ] In the depth jump, 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.
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.
The height used by most athletes is usually quite low in the early stages of training. The key is how high the athlete jumps in relation to the height of the takeoff platform. Technique and jump height are most important at this time. While the body is dropping, the athlete consciously prepares the muscles for the impact by tensing the muscles. The flooring upon which the athlete drops down on should be somewhat resilient, mainly for prevention of injury.
Upon making contact with the floor, the athlete then goes into slight leg flex to absorb some of the force for safety. However, the main role played by the muscles and tendons is to withstand the force that is experienced in the landing. This force is withstood in eccentric contraction. When muscle contraction is sufficiently great, it is able to stop the downward movement very quickly.
This phase is sometimes called the phase of amortization in which the athlete absorbs some of the force and stops downward movement by the strong eccentric contraction of the muscles. The strong eccentric contraction prepares the muscles to switch to the concentric contraction in an explosive manner for takeoff.
When the athlete drops down to the floor, the body experiences an impact upon landing. The higher the height of the step-off platform, the greater the impact force upon landing. This creates a shock to the body which the body responds to by undergoing a strong involuntary muscular contraction to prevent the body from collapsing on the ground. This in turn produces great tension in the muscles and tendons which is then given back in a return upward movement.
The faster the change in the muscular contractions, the greater the power created and the resulting height attained. The greater the shock forces experienced on landing , the stronger the eccentric contraction will be, which in turn produces even greater tension. This tension, which is potential force, is then given back in the return movement when the muscular contractions switch to the concentric or shortening regime.
The greater the time between receiving the forces and giving them back, the less is the return and the less the height that can be achieved in the jump. Most of the lengthening and shortening occurs in the respective muscle tendons which have greater elasticity.
Another way of saying this is that the faster the switching from the eccentric to the concentric contraction, the greater will be the force produced and the greater the return movement. The speed of the switching is extremely fast, 0. For example, high-level sprinters execute the switch from the eccentric contraction that occurs when the foot hits the ground to the concentric contraction when the foot breaks contact with the ground in less than 0. In world-class sprinters, the time is approximately 0.
The main criterion is that the athlete is jumping as high as possible on every jump. If the athlete gradually improves his jump height, the same platform height is continued until increases in jump height are no longer observed. At this time, takeoff height is increased by a few inches. If the athlete continually fails to jump very high, the height of the drop-down is lowered somewhat. Rather than developing greater explosive power this height leads to more eccentric strength development.
This occurs when the intensity of the forced involuntary eccentric contraction upon landing is greater than the muscles can withstand. In addition, the athlete will not be able to execute a quick return fast transition between muscular contractions , which is the key to successful execution of explosive plyometrics.
Because of the forces involved and the quickness of execution, the central nervous system is strongly involved. Doing so will lead to great fatigue, and, according to Verkhoshansky, sleep disturbances. This indicates that athletes must be well-prepared physically before doing this type of training.
In essence, the athlete goes into a slight squat crouch upon landing in which the hip, knee, and ankle joints flex. The takeoff or jump upward is executed in a sequence initiated by hip-joint extension followed by knee-joint extension which begins during the hip-joint extension. As the knee-joint extension is taking place, ankle-joint extension begins and is the only action that occurs as the takeoff breaking contact with the ground takes place.
All three actions contribute force to the upward jump, but the knee-joint extension is the major contributor. These jumps are effective for athletes who execute skills in their sport that do not require explosive type muscular contractions.
An example is long-distance running in which the runners execute repeat actions of 20 to 30 consecutive jumps and other cyclic-type activities such as leaping for multiple repetitions. In essence, they are effective in the early stages of learning how to do plyometric exercises and for preparing the muscles for explosive or quick jumps.
These jumps are similar to those done by youngsters in the playground or in neighborhood games and as such, do not require additional preparation. Athletes, regardless of their level of expertise, can undertake such jumps in the initial stages of training.
When athletes who have been doing plyometrics without regard to time of execution first attempt to execute explosive plyometrics, they often fail because the time of execution is too long. This occurs quite often in the depth jump. The athlete usually sinks drops too low which takes too long to make the transition from the eccentric to the concentric contraction.
As a result, the exercise becomes a jump-strength exercise and not a true plyometric one. Jump technique remains the same regardless of whether it is a true plyometric exercise or a jump exercise. The hips, knees, and ankles flex when landing and the joints extend on the upward return.
The sequence and overlapping in the sequence is basically the same, beginning with the hip extension, followed by knee extension, and ending with the ankle-plantar flexing. The major differences in execution are the depth of the landing and the time of executing the switch from the eccentric to the concentric contraction.
Studies have been conducted testing ten various plyometric exercises on overall performance during jumping examined by EMG, power, and ground reaction force GRF. Of the ten exercises, the single-leg cone hops, box jumps, tuck jumps, and two-legged vertical jumps produced the highest EMG values, alluding to greater motor recruitment.
Power was examined in dumbbell jumps, depth jumps, countermovement jumps, squat jumps, and tuck jumps which all produced the higher power scale readings. In terms of athletic performance and training, the plyometric movements that utilize total body vibration produced an overall increase in performance output. A recent study examined two groups using the same plyometric protocol in combination with weight training , one using high loads and the other utilizing small loads, and similar decreases in power were found.
This shows that the plyometric exercises themselves had a greater effect in the decrease in power output rather than the type of weight training. Plyometric exercises involve an increased risk of injury due to the large force generated during training and performance, and should only be performed by well conditioned individuals under supervision. Good levels of physical strength , flexibility , and proprioception should be achieved before beginning plyometric training. The specified minimum strength requirement varies depending on where the information is sourced and the intensity of the plyometrics being performed.
Core abdomen strength is also important. Flexibility is required both for injury prevention and to enhance the effect of the stretch shortening cycle. In fact, some advanced training methods combine plyometrics and intensive stretching in order to both protect the joint and make it more receptive to the plyometric benefits. Further safety considerations include: Age: should be taken into account for both prepubescent and the elderly because of hormonal changes. Technique: a participant must be instructed on proper technique before commencing any plyometric exercise.
He or she should be well rested and free of injury in any of the limbs to be exercised. Plyometrics are not inherently dangerous, but the highly focused and intense movements used in repetition increase the potential level of stress on joints and musculo-tendonous units. Therefore, safety precautions are strong prerequisites to this particular method of exercise.
Low-intensity variations of plyometrics are frequently utilized in various stages of injury rehabilitation, indicating that the application of proper technique and appropriate safety precautions can make plyometrics safe and effective for many people. Benefits[ edit ] Many professional and Olympic athletes use plyometrics training to improve muscular strength and jumping abilities which therefore increases their power. There are varying levels of intensity to plyometrics.
Another benefit of plyometrics are that you can vary your level of intensity which means anyone looking to improve strength and jumping training can be involved regardless of fitness.
With there being so many exercises this means you are less likely to get burned out and have a wide range of exercises to choose from. It also increases muscular strength and endurance, also increases metabolic rate which increases weight loss and heart rate.
The weight is held or worn. The additional weight may be in the form of a barbell, trap bar, dumbbells, or weighted vest. For instance, a vertical jump whilst holding a trap bar or jumping split squats whilst holding dumbbells.
In addition, a regular weight lifting exercise is sometimes given a plyometric component, such as is found in a loaded jump squat. Jumping onto boxes or over hurdles whilst holding weights is not recommended for safety reasons. The advantage of loaded plyometric exercises is that they increase the overall force with which the exercise is performed.
What Is Plyometrics?
Kilar Squat with a 90 degree turn 3. Thus, adjust the weight according to your capabilities for best results. The jumps should be executed for plometrics, but not so far that they slow you down in the takeoff. Do not land with the toes pointed so that you land on the ball of the foot close to the toe area. Plyometrics The specified minimum strength requirement varies depending on where the information is sourced and the intensity of the plyometrics being performed.
EXPLOSIVE PLYOMETRICS YESSIS PDF
Method[ edit ] In the depth jump, 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. 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.