Looking to add another dimension to your workout and performance capabilities?
If so, plyometric training could be for you. If you haven't heard of plyometrics, they are a series of exercises that combine movements such as jumping, bounding, skipping and throwing in a quick and repetitive manner. They have been used for many years in sport-specific training, but not as often in health clubs and gyms.
Using plyometric drills has been shown to improve rate of force development (speed and agility) and explosiveness (power). If you don't care about these aspects of performance, than including plyometrics could simply add variety to your workouts and improve joint stability.
How They Work
The principal behind plyometrics is rapid force development. For example, a typical plyometric drill is repetitive vertical jumps. As you land from one jump you must generate enough force to jump again immediately. By doing this you are overloading the muscle and building explosiveness.
Stretch-Shortening Cycle
Plyometric drills are valuable to a training program because they take advantage of the stretch-shortening cycle within the muscle(s). Using the jumping example once more, the muscle's elastic components are able to store energy when they are stretched (landing), and then that energy is used as the muscle starts to contract (concentrically) to take off again. The force produced is much greater than if you were to jump without first stretching the muscle.
To further clarify, the stages of the stretch-shortening cycle can be compared to a biceps curl. When the resistance is lowered, the biceps lengthens (stretches) as it eccentrically contracts. Then, when the weight is curled upward, the biceps shortens during the concentric contraction. 
In the context of plyometrics, the cycle occurs quickly or it is ineffective. If the stretch-shortening cycle is slow the energy that could be stored in the elastic components (tendons, muscles) is lost as heat and cannot be used in a subsequent contraction. To optimize the stretch-shortening cycle, it must be performed rapidly.
Also, your ability to use the stored elastic energy is influenced by the amount your muscle is stretched, and the amount of time that the muscle pauses in the stretched position. Once again, if it remains stretched too long, usable energy is lost as heat. If the eccentric contraction (stretch) is of short range, and performed quickly without stopping in the stretched position, the force of the concentric contraction will be maximized.
Therefore, when performing plyometrics, it is important to make your movements quick, smooth and avoid completely stopping the movement when your muscles are stretched.
There is also a neurological aspect to the stretch-shortening cycle as the muscles' reactive properties can be improved with plyometric training. It can stimulate various neurological mechanisms to help increase muscle recruitment over a shorter period of time. Researchers suggest plyometric training increases neuromuscular coordination and improves neural efficiency.
Improvements In Performance
Performance enhancements have been reported in many scientific studies using plyometrics. Many studies are sport-specific, using exercises directly related to the activity.
On the other hand, some studies - using general exercises - in combination with strength training, have reported increases in vertical jump height and overall power. Improvement in performance is thought to be mainly because of neural adaptations, improved neuromuscular coordination and an increased ability to utilize stored elastic energy for muscle contraction, rather than morphologic changes. Because of the neural contributions to this type of training, it is perfect for strength-trained individuals who have built a solid base and have experienced morphological adaptations. The drills will be a different challenge for your neuromuscular system.
Neurological Adaptations
The neurological adaptations thought to result from plyometric training include increased motoneuron discharge frequencies, a change in the recruitment of motor units and increased sensitivity of the stretch/reflex within trained muscles.
Training Considerations
You may be asking yourself why you couldn't just perform typical weight-training exercises at a fast rate. Well, the difference is that you really can't be "explosive" in your actions because you have to bring the weight to a stop. Also, you want to use reduced resistance for these types of exercises to make them fast and explosive. The more weight used, the slower you have to make the movements, and the higher the opportunity for injury. 
1. Safety
These activities are ideal for those with a strong weight-training background: Large forces are produced during and your muscles must be strong enough to handle them. In addition, because of the nature of the training, and the impact involved with the various jumping, bounding and hopping drills, it is important to wear proper footwear and find a place with good, shock-absorbing floors. In the gym, if the floor around the training area isn't appropriate, an aerobics studio is the best place to perform the exercises.
2. Technique
Proper technique is essential to not only improving your power and speed, but for prevention of injury. Like any strength-training exercise, form and effort are essential to make gains. The rate of the stretch-shortening cycle is highly influenced by the amount of effort you put into each repetition. By increasing the rate of the stretch-shortening cycle you can maximize the benefits of this type of training.
3. Frequency
As with weight training, the same muscle groups should not be trained on consecutive days. One or two times each week is recommended for this type of training, except if you are training upper-/lower-body muscle groups on different days. Two to four times each week is appropriate in this case. At least 48 hours of recovery time is critical to prevent injury and overtraining.
4. Volume / Intensity
Intensity of initial workouts should be low, starting with basic drills like stationary jumps in various directions (side to side, diagonal). Intensity is based on the stress placed on your muscles not the amount of effort (Allerheiligen, 1995). If intensity is low, then volume can be high. As you get further along in your training, intensity should increase and volume be reduced. In plyometric training, volume is usually expressed as the number of foot/hand contacts. For example, if you were to perform four sets of 10 single-leg bounding jumps that would be 40 contacts. One to two hundred foot contacts are appropriate when starting.
Lower Body Exercises And Their Relative Intensities ...
| Drill
|
Intensity
|
| Low Intensity
|
|
| 2-Leg Bounding Jumps
|
Moderate Intensity
|
| 1-Leg ZigZag Bounding Jumps
|
Moderate Intensity
|
| High Intensity
|
|
| Drop Jumps
|
High Intensity
|
5. Recovery
Depending on the exercise, you must rest between reps and/or sets. For the lower intensity or continuous drills, resting between repetitions in not necessary. But between high-intensity drills like drop jumps or box jumps, a recovery of 10-20 seconds between each jump is important. Also, the rest between sets depends on the intensity of the exercise. A rest of 30 seconds up to one minute between sets of high-intensity exercises is suggested. Plyometrics are based on the assumption that, for each repetition, the athlete is putting forth maximal effort, so adequate recover is important.
And as with any weight-training program, two consecutive days of plyometric drills using the same muscle groups are not recommended.
How Can Plyometrics Fit Into Your Strength Program?
The ideal scenario would be to combine your upper body weight workouts with lower body plyometrics. For example, the time that it took you to perform one set of bench presses would be adequate recovery from a set of lower body plyometrics. 
Finding a good place to do these exercises might be challenging, but you can find many pieces of apparatus around the gym to use for jumping and throwing exercises. A barbell with various-sized plates on the ends can be used to perform lateral jumps over. Medicine balls found or small dumbbells can be used for upper-body exercises, and stairs or steps can be used in the place of boxes.
Once you have mastered weightless explosive exercise, you can start to add resistance. Make sure the weight is still relatively light so you don't limit the explosiveness of your movements.
See the section on sample programs for specific ways to include plyos in your regular workout.
Examples Of Typical Exercises
Note: All exercises should be performed as described above - quick, powerful and smooth.
Upper Body Exercises
Throwing Exercises Using A Medicine Ball - view exercise
If you have room you can release the ball over your head; but if there is not enough room, stop the movement when arms are extended overhead.
Catch And Throw
This exercise can be performed on your own or with a partner. It can be done from overhead with your body staying in one spot (see Diagram 2a and 2b) or as a crunch, catching the ball sitting up, laying back with arms extended and ball overhead and releasing to partner as you sit up. If you don't have a workout partner, do not release the ball, but follow the same movements.
Side-To-Side / Extended Arms - view exercise
This exercise can be performed standing up, sitting down or sitting with upper body leaning slightly back (for a greater abdominal workout). Using two hands, hold the ball extended from chest. Move ball quickly from side to side, stopping the movement, and starting in the other direction as quickly as possible.
Stretch-Shortening Push-Ups
Drop yourself off a raised platform in a push-up position ... to a pushup with a narrow hand position. 
Note: You can also do explosive pushups by pushing yourself off the ground, landing, then repeating.
Lower Body Exercises
Tuck Jumps - view exercise
These can be done in many directions (one spot; side to side; forward/ backward, etc.).
Jumping Onto Box And Backward Down
Starting at low height is important. Gradually increase the height to increase the difficulty of the exercise.
Explosive Jumps Over Box - view exercise
As with the previous exercise, box height increases make this drill more difficult.
Drop Jumps Off A Box
Start at low height and gradually increase. Anything greater than 60 centimeters (approximately 24 inches) reduces the benefit of the drop jump.
Rebound Jumps
Drop from a set height and then jump vertically immediately upon landing. If you have the box too high you won't reap the benefits of the exercise. Refer to the recommendations in the previous exercise.
Sample Starting Programs
Day 1:
- Legs - Using Weights
- Upper Body - Using Plyometric Exercises (below)
Complete your usual lower body weight workout with adequate rest between sets and exercises. Following this, an upper body plyometric session can be completed.
Note: Notice the number of total repetitions (100-200 is recommended when starting).
Virtual Upper Body Plyometrics
| Exercise
|
Repetitions
|
Sets
|
| Overhead Throws with a Medicine Ball
|
10
|
3
|
| Catch And Throw
|
10
|
3
|
| Side-To-Side Rotation with Medicine Ball
|
10
|
3
|
| Explosive Push-Ups
|
10
|
3
|
| Explosive Dips
|
10
|
3
|
Print Off The Virtual Upper Body Plyometric Routine HERE!
Day 2:
- Biceps And Back - Using Weights
- Lower Body - Using Plyometric Exercises (below)
Whatever your muscle group combination might be, an upper body weight routine can be combined with lower body plyometric exercise. Once again, it would be appropriate to do plyos either before or after your weight routine.
Virtual Lower Body Plyometrics
| Exercise
|
Repetitions
|
Sets
|
| Vertical Jumps
|
10
|
3
|
| Tuck Jumps
|
10
|
2
|
| Jump Up Onto Box (height approx. 10cm)
|
10
|
3
|
| Drop Jump Off Box (add rebound jump to increase difficulty)
|
10
|
3
|
Print Off The Virtual Lower Body Plyometric Routine HERE!
Day 3:
- Triceps, Shoulders, And Chest - Using Weights
- No Plyometrics
Day 4:
- Aerobic Exercise
- Rest
Day 5:
- Same as Day 1
Day 6:
- Same as Day 2
Day 7:
- Same as Day 3
Alternatively, you can do a whole body plyometric routine twice each week on non-consecutive days. Whatever plan you choose, the key is to start easy and gradually increase the difficulty of drills by either increasing the volume (number of reps or sets), or the intensity (adding height of the box/step or increasing the weight of the medicine ball).
Virtual Total Body Routine
| Exercise
|
Repetitions
|
Sets
|
| Side-To-Side Jumps
|
10
|
4
|
| Tuck Jumps
|
10
|
3
|
| Catch And Throw Using Medicine Ball
|
10
|
3
|
| Side-To-Side Rotations Using Medicine Ball
|
10
|
3
|
Print Off The Virtual Total Body Plyometric Routine HERE!
Plyometrics have been shown to improvement power and speed. Try adding them to your workout for a while and see what they can do for you!
Thanks,