Without really knowing it, you will have probably preformed plyometrics during a sporting situation, group fitness class or gym based workout. Plyometric training was first known as ‘jump training’ and was first used by eastern European athletes during the 70’s. The American field and track coach Fed Wilt first used the term plyometrics in 1975. Over the years plyometric training has quickly become an essential part of explosive speed and power training by athletes worldwide.
Plyometric exercises enable the muscle to reach maximum strength in the shortest amount of time, this action is also known as power. Athlete power directly affects an individual’s ability to jump, change direction and sprint, fundamental components of most sports. The basic physiological mechanism targeted by plyometric training is known as ‘the stretch-shorten cycle’. There are two important factors affecting the stretch-shorten cycle, elasticity and stretch reflex of a muscle. The elasticity of a muscle is important during the eccentric phase ( leg muscles lengthen before jump). As a muscle rapidly lengthens, energy is stored in the elastic components of the muscle (tendons and cross-bridging of the muscle fibers), which then can be added to the concentric phase (pushing off during jump). The stretch reflex mechanism is seen during the knee tap test preformed by doctors. When a tendon is rapidly stretched, the stretch reflex mechanism will cause the attached muscle to contract with equal force. It is very important that there is little delay between the action of the stretch shorten cycle and the concentric phase of the movement. If the time delay between eccentric and concentric phase of a plyometric exercise is too long the stretch-shorten cycle will not help produce extra power. When performing plyometric exercise keep contact time with the ground as short as possible.
There are a number safety and technique concerns needed to address when performing plyometric exercises. Safety concerns such as warm-up; footwear, exercise surface and level of intensity.
Plyometric training places great stress on the joints, tendons and muscles. The rapid change between the eccentric loading of the muscles and the concentric phase of the movement produces great force. With this in mind always warm-up and perform specific stretches before commencing plyometrics. The best way this can be achieved is by performing 5-10 minutes of low intensity cardiovascular exercise (jogging, skipping or stationary bike). Stretching should be preformed in a dynamic fashion. Dynamic stretching drills are simply, stretching with movement.
You may have seen sprinters skipping or marching down a track before a race or training, these are example of dynamic warm-up drills used before plyometric training. Do not perform long duration static stretches, this will only tone down the stretch-shorten cycle and will hamper your muscles ability to produce force quickly. To prevent injury always wear supportive footwear during training. Stay away from running shoes with too much shock absorption. Forces need too be transferred quickly between the eccentric and concentric phase, running shoes are designed to slow this force and will decrease the effectiveness of the training. Make sure the surface you are training on is even with no obstacles that can cause injury. The harder the training surface the greater the force will be transferred though the stretch-shorten cycle. If the surface is too hard (concrete or hard-wood) there is an increased chance of injury.
Limit the amount of time-spent training on this type of surface. Plyometrics exercises place great stress on the body. Because of the high intensity nature of this training always seek help from a qualified instructor, coach or personal training when designing a programme. For more information on plyometrics there are many books, video’s and dvd’s dedicated style of training. The internet is always a great source of information, simply do a search on www.google.co.nz.
Performing the exercises.
Before commencing plyometrics seek clearance from a medical practitioner. A six-week conditioning programme designed by a qualified instructor should be completed before commencing this any of these exercises. If you have are carrying any injuries or excess body fat check with a qualified instructor before commencing any plyometric style exercise.
The following exercises are not to be used as a finished programme, merely as an addition to an individual existing exercise programme. Replace an existing exercises with a corresponding plyometric exercise listed below.
Make sure you are using supportive footwear and the training surface is even and clear of obstacles. . A warm-up of 5-10 min cardio should be completed at the start of the workout. The first 2 sets of plyometrics should be preformed at 50-75% intensity.
5-5-5 squat jumps 2-3 10-15 60s
Single leg side to side jump with a vertical squat jump 2-3 10-15 60s
Power drop 2-3 10-15 60s
Plyometric Reverse crunches 2-3 10-15 60s
Do not hold your breath, breath out on exertion. Select a load suitable for the rep range. Maintain technique throughout exercise, once you lose your technique stop!
1. 5-5-5 squat jumps
This is a great exercise for improving an individual’s vertical jump. 5-5-5 squats also tone the lower limbs (hips and thighs) without bulking muscles, which sometimes occur with heavy traditional squats. Great for sports such as: netball, basketball, volleyball and skiing.
Stand with feet shoulder width apart. For increased load depending fitness level hold a 2-6kg medicine ball close to your chest. Keep eyes on the horizon, abdominals strong and the chest up throughout the movement.
Move with hips first then knees. Squat as if sitting into a chair, keeping the abdominals strong. Stop decent if the heels start to rise or the pelvis tilts backward. Stop when the thighs are parallel to floor.
Perform 5 slow controlled squats while keeping the ball on your chest. Next, perform 5 drops squats by dropping quickly in the down phase and rising slowly in the up phase. Last, perform 5 explosive squat down and up phase fast. As you explode in the up phase drive the medicine ball as high as you can without letting it go.
2. Single leg side to side jump with a vertical squat jump
The ability to change direction quickly is needed in many sports. This exercise is designed to a produce explosive change in direction. With a focus on the abductors (outside thighs) it also has a great toning affect. Great for sports such as: Netball, basketball, volleyball soccer and rugby.
Start in a vertical position on one foot with knees slightly bent. Use a pole or line to jump across.
Jump laterally over the line or pole landing on the opposite foot. As you land jump explosively in a vertical direction. Repeat exercise in the opposite direction until rep range is reached.
3. Power drop
This is a partner-assisted exercise. The focus of this exercise is to increase explosive power of the chest, shoulders and triceps. Great for sports such as: netball, basketball, tennis and boxing.
Lie in a supine on the ground with arm raised above your chest. Your partner stands on a box with medicine ball in outstretched arms.
When the partner drops the ball catch it and propel it back to the partner in an explosive manner.
4. Plyometric Reverse crunches
You will need an exercise partner to complete this exercise. The focus of this exercise is to increase an individual’s ability to produce directional change using the abdominals. Many abdominals are performing in a slow and controlled manner, which is great for tone and shape but does little for functionality needed for sport. If you find traditional abdominal exercises no long produce a training affect try this high intensity exercise.
Lie in a supine position on the ground. Have your partner stand above your head with feet shoulder width apart by your ears. Grip tightly around your partner’s ankle, be careful not to pull your partner over when performing this exercise. Raise your legs straight up toward your partner’s hands.
As you raise your legs towards your partner she/he should push your legs away toward the ground. Resist this move and more raises your legs quickly to the starting position. Repeat until exercise rep range is reached.