SITE DESCRIPTION

TKDTutor provides martial arts students with information about all aspects of taekwondo and the martial arts in general and helps potential students avoid fraudulent organizations, schools, instructors, and concepts.

Training>Exercise>Plyometrics

↩ Back

Plyometrics

Intro

Speed and strength are integral components of fitness found in varying degrees in virtually all athletic movements. It is especially useful in martial arts that use jump kicks and leaping or lunging hand attacks. Simply put, the combination of speed and strength is power.

For many years, coaches and athletes have sought to improve power to enhance performance. Throughout this century and no doubt long before, jumping, bounding, and hopping exercises have been used in various ways to enhance athletic performance. In recent years, this distinct method of training for power or explosiveness has been termed plyometrics.

Plyometrics is any exercises where the muscle is stretched (loaded) before it is contracted. A good example is push-ups with a clap between each push-up. Your muscles (pectorals in this case) are elongated and loaded by the downward force of your body, then immediately you must contract the muscles to push yourself back up to clap.

What is plyometrics good for?

Plyometrics is one of the best ways to improve power. When a person performs a specific resistance movement, such as jumping, the fastest would be said to have more power. Therefore, power derives not just from the contraction of a muscle, but also how fast it contracts.

Research has shown that a muscle will contract the fastest after it has been loaded. Therefore, you can jump higher if you crouch down and then immediately jump up than if you would have had you started from the crouch. Research has also shown that practicing plyometrics will decrease the time it takes for the muscles to contract, resulting in more power.

The golden rule of any conditioning program is specificity. This means that the movement you perform in training should match, as closely as possible, the movements encountered during competition. Martial artists use all parts of their bodies during sparring, so they need to train both their upper and lower bodies.

Are plyometrics dangerous?

Since so many exercises may be considered plyometrics, some of them may dangerous. Jump squats are a great example. This is where you perform a regular squat (with weight) and jump at the top of the motion coming off the ground 1-2 inches. You perform this exercise with about one-third of your maximum squat weight. This is one of the best exercises to increase your jumping ability, however, it is also a dangerous one. On the other hand, performing the both feet ankle hop is very safe.

A good general test to see if you are ready for plyometrics is to stand and jump up as high as you can. Measure this height (chalk on your fingertips and a clean wall is a good way to measure). Then jump off an 18-inch high box and jump as high as you can. If you cannot reach as high as you could on the ground, you would be better off hitting the weights and coming back later.

As with any exercise program, obtain medical permission, start easy, and stop if you feel any ill effects.

How muscles operate

Muscle contractions

There are three types of muscle contractions:
  • Eccentric. This is when the muscle lengthens under tension. It is used to decelerate the body, such as when lowering into a squat with a loaded barbell on the shoulders. 
  • Isometric. This occurs when the muscle is under tension but not moving, such as when trying to rise from a lowered squat and the weight is too heavy to lift.
  • Concentric. This is when the muscle contracts under tension. It is used to accelerate the body, as when rising from a lowered squat.
When a fighter dives in for a takedown, he or she may initiate the motion with a backward step, which "loads" the muscles of the back leg as they stretch and lengthen in an eccentric contraction. For an instant, the muscles are in isometric contraction in preparation for an explosive concentric contraction as the leg drives forward for a successful takedown. It is important to remember that the rapid stretch of the muscle must be followed by an immediate rapid concentric contraction. Any delay will result in this stored energy being lost.

The maximum force that a muscle can develop is attained during a rapid eccentric contraction. However, muscles seldom perform one type of contraction in isolation during athletic movements.

When a concentric contraction occurs (muscle shortens) immediately following an eccentric contraction (muscle lengthens), the force generated may be dramatically increased. As a muscle is stretched, much of the energy required to stretch it is lost as heat, but some of this energy may be stored by the elastic components of the muscle. This stored energy is available to the muscle only during a subsequent contraction. This energy boost is lost if the eccentric contraction is not followed immediately by a concentric effort. To express this greater force, the muscle must contract within the shortest time possible. This whole process is frequently called the stretch-shortening cycle and is the underlying mechanism of plyometric training.

Types of muscles

For decades, we have been taught that to maintain basic aerobic fitness we need three 20-minute aerobic training sessions per week. This is still good advice, but, as active martial artists shouldn’t we do even more? The answer is no! To build quicker, more powerful kicks, you do not need extra aerobic activity, you need to train your muscles to kick quicker and more powerfully.

Everyone has some percentage of two basic types of muscle fibers: slow-twitch (Type I) and fast-twitch (Type II). The relative percentage of each type in each person is the result of genetics and training.

Slow-twitch fibers are used in sustained aerobic activity, such as long runs. When you engage in aerobic activities for over 30 minutes you are developing this muscle fiber type and its supporting enzyme system. Developing these muscle fibers does not help you kick quicker or more powerfully because slow-twitch muscles have limited potential for both rapid force development and low anaerobic (high intensity) power.

Fast-twitch muscles are used in short bursts of anaerobic activity, such as short sprints and the bursts of activity used in sparring. To increase kicking speed and power, you need to develop your fast-twitch muscle fibers.

Specializing in aerobic training develops mitochondria in muscle fibers. Mitochondria are the oxygen cells that enable you to run extended distances. However, an increase of mitochondrial cells deters the development of fast-twitch muscles, which reduces the concentration of anaerobic enzymes and decreases muscle mass. Both of which we do not want to do as martial artists since this will decrease the speed and power of our kicks. Generally, long-distance runners have a low vertical jumping ability, whereas kickers want to be able to jump high.

To win a sparring match, you certainly need some aerobic training so you can maintain your energy output throughout a match, but to be able to perform kicks that score, you need a lot of anaerobic training. Therefore, you should perform aerobic training for 20-minutes, 3 to 4 times per week, at approximately 70% of your maximum heart rate (220 minus your age), but then you need to perform lots of intense anaerobic training.

One way to do this is with resistance training in the form of squats or lunges using high weights and few repetitions. Sparring competitors who want to last through several rounds, need to develop their local muscular endurance (LME). To do this with resistance training, use light weights and perform many repetitions, perhaps 20 to 25, to develop the ability to deliver successive kicks. In addition to resistance training, you can perform short bursts of high-intensity effort on the heavy bag, run wind sprints, and, of course, perform plyometrics.

Plyometric exercises

For increasing your speed

While all the above exercises will also increase your speed (leg speed), these exercises focus more on movement to build speed.
  • Zig Zags. Stretch an elastic cord about a foot off the ground between to objects. While on one foot, hop over the rope to the other foot. Hop back and forth over the rope. 
  • Side to side ankle hops. Same as above, but instead of remaining in place, jump the feet 2 to 3 feet side to side. 
  • Bounding and hurdling. While in a slow run, use oversized strides to spend extra time in the air. Two-legged bounding reduces the impact, but to increase the intensity, one-legged bounding, or hopping, may be used. Bounding upstairs is a useful way to work on both the vertical and horizontal aspects of the running action. 
  • Sprints. Sprints are considered plyometrics since the force of your body coming down during a step loads the hamstring. 

 For increasing your vertical jump

These exercises use your body weight and gravity to load muscles before contraction. The forces you generate are much larger than could be safely accomplished using conventional resistance, such as weightlifting. The exercises may be combined, such as jumping off a box before jumping up to perform a rim jump.

While plyometric will increase your vertical jump, maintaining form is also important. Crouch to a point where your knees reach a 90-degree angle.

Swinging and throwing your arms up as you jump decreases the weight that you must push off the ground, and the inertia of your arms going up will help pull the rest of your body up. This motion is okay for exercises, but when martial artists perform jump kicks their arms are kept in a guard position.

Also, the faster you are moving before the jump, the higher you can jump, as in a running start. As you jump, you transfer the horizontal speed to vertical speed. Therefore, high jumpers use a running start to jump much higher than they could from a standing start. For martial artists, this is only useful if the opponent is unaware or stunned so he or she cannot react since it takes time for the attacker to cover the running distance.
  • Both feet ankle hop. Keeping feet together and, while remaining in one place, hop up and down using only your ankles and calves. Concentrate on getting as high as you can and exploding off the ground as soon as you land. 
  • Astride jumps. Start with feet together, knees slightly bent. Bounce on the toes and move your feet out to each side about shoulder-width apart. Bounce on the toes and bring the feet together again.
  • Compass jumps. Start with feet together with the knees slightly bent. While always staying on your toes with the feet together, bounce and move your feet forward to the north, the bounce back to the starting point. Repeat the action to each of the 3 other compass points, sought east, and west. b
  • Rat-a-tats. Always start with knees slightly bent and stay on your toes. Run in place while bringing the toes no more than an inch off the ground.
  • Walking on toes. Perform the following drills with a high knee action, with the arms swinging in an exaggerated sprint action, with the whole body erect and relaxed. Perform 2 or 3 sets over 20 to 30 yards. Variations of the exercise include:
  • Perform with your feet pointing forward.
  • Perform with your feet pointing inward 45 degrees.
  • Perform with your feet pointing outward 45 degrees.
  • Repeat the above while skipping.
  • Repeat the above while jogging.
  • Heel walk. Walk on your heels.
  • Ankle raise. Stand with your back one foot away from a wall. Lean back until buttocks and back touch the wall, keeping heels on the ground. Flex ankles so toes rise as high as possible, then let the feet sink back, not letting toes touch the floor
  • Rim jumps. Stand under a basketball rim. Jump up touching the rim (or net or whatever) with alternate hands. Concentrate on getting as high as you can and exploding off the ground as soon as you land. 
  • Drop jumping. Drop (not jump) to the ground from a raised platform or box. Immediately jump up. The drop pre-stretch the leg muscles and the vigorous drive upwards is the concentric contraction. The exercise will be more effective the shorter the time the feet are in contact with the ground. The loading in this exercise is governed by the height of the drop. Drop jumping is a relatively high impact form of plyometric training and should not be performed until accustomed to lower impact alternatives, such as both feet ankle hopping.
  • Box to box jumps. Place two boxes that will support your weight about 3 feet apart. Standing on one box, step (NOT JUMP) off and immediately jump back onto the other box. Turn around and repeat. The difficulty of this exercise is increased as the height of the boxes is increased. Once again, concentrate on getting as high as you can and exploding off the ground as soon as you land. 

For increasing your lower body power

  • Rhythm hop jog. This is basically a slow jog, except that every time a foot contacts the ground, you leap off it as quickly as possible.
  • Power hop jog. Start with a slow jog. After three or four steps, hop off the right foot as high as possible. When the left foot contacts the ground, reduce the amount of time that it is in contact with the ground as much as you can, and spring off the left foot explosively, attaining as much height as you can. Continue until each leg has made eight to ten hops. The two important factors are the height and the length of time that the foot is in contact with the ground.
  • Speed hop jog. Speed hop jog is the same as the power hop jog exercise described above except that it has only one emphasis, speed, height is not important. The length of time that the foot is in contact with the ground is of utmost importance. It should feel more like a skip than a hop. Since hopping upward slows the muscular contractions too much, it is necessary to hop forward. If the right foot is driving off the ground, the left leg swings forward, almost straight. When the left leg contacts the ground, it drives forward with a strong pulling action of the hamstring muscles. In this method, the foot is in contact with the ground for only a small fraction of a second. 
  • Two-legged speed hops. The basic movement of the two-legged hops is the broad jump, performed repeatedly. Movement is the same as the standard broad jump except that all movements are kept short and quick. The knees do not bend much, and the arms do not have time to swing fully. Hop forward ten times, each time making sure that the feet are in contact with the ground for as little time as possible. Each hop should be about two feet.
  • Two-legged power hops. Two-legged power hops require that you drive upward as much as possible, only moving forward about 18 to 24 inches. Compared to two-legged speed hops, the knees bend considerably more, the arms drive up much more, to get more height.

For increasing your upper body power

  • Push-ups with a hand clap. Push-ups with a hand clap in between are a particularly vigorous way to condition the arms and chest. The pre-stretch takes place as the hands arrive back on the ground and the chest sinks. This is followed quickly by the explosive upwards action. Once again, to get the best training effect, keep the time in contact with the ground to a minimum.
  • Medicine ball. Lie on the ground face up. A partner then drops a medicine ball toward your chest. Catch the ball (pre-stretch) and immediately throw it back. This is another high-intensity exercise that should only be used after some basic conditioning.

Using strength shoes

A strength shoe is a shoe with an elevated sole, but the sole is only on the ball of the foot so the calf can hang free, forcing it to be stretched (thus loaded) on every step. Strength shoes make every step a plyometric exercise for the calf. Since they only work the calf, you must do regular plyometric exercises in them to work the other muscles. Be aware that the calf plays a limited role in jumping and acceleration, only about 30%, so while strength shoes will help, they are just a tool for a good plyometric regime.

  ↩ Back

No comments: