Plyometrics is not a new concept. It has been used for improving performance for years. It is just recently that it has gained wide attention. The word Plyometrics has been in use since the 1960's. Plyometric training is based on using movements that are similar to the type of movement that would be done in a particular sport or activity to improve performance. Several studies have demonstrated that a combination of Plyometrics and weight training is far more effective in improving speed and strength (power).

Plyometrics, employed to develop power and explosive responsiveness, uses the Stretch-Shorten Cycle (SSC). The whole idea is to develop the most amount of force in the shortest possible time. When a muscle is flexed or shortened, it's under tension and will react with a more powerful and explosive contraction due to stored elastic energy. Unlike most other aerobic exercises, gravity becomes a major factor in the workout routine.

Strength and flexibility are prerequisites for Plyometric training. The laws of Physics apply. A one-g force is equal to your weight. Two or more g's of force may be exerted by an individual during a jump. For example, a 250-pound (114 kg) individual would subject forces equal to or greater than 500 lbs (227 kg) of pressure on hip, knee and ankle joints. A 100 (45 kg) pound person would experience force equal to or greater than 200 pounds (91 kg). It's obvious that too much Plyometric training can be damaging to joints, as is the case with all types of exercise.

As is the case in all other types of training, technique is the key. In this case, as they say in piloting, landing is the most important of all. When the body meets the ground is where the potential for damage is highest. Land like a cat. The joints should not be stiff. Allow the legs to act as a shock absorber. The best way to land is to pretend that you are jumping off of a step behind someone and you don't want them to hear you land. This is true for running as well. Use the body's natural ability the absorb shock. If you hear a lot of noise when you run or land from a jump, remember that energy was used to create that noise and your body was the instrument. Keep it quiet. Some people advocate landing on the ball of the foot and some on the full foot. Either way, energy must smoothly and evenly transfer up the leg. The use of arms in a jump has been shown to contribute up to 10% of the jump results.

When a muscle is eccentrically contracted (stretched or elongated) and then subsequently concentrically contracted (flexed or shortened) the speed of the contraction is increased thereby creating a more powerful contraction similar to a stretched rubber band. In the real world, muscles undergo a more complex movement involving muscle groups and greater neural interaction than what can be achieved in regular weight training.

There is some controversy as to whether plyometrics are safe. The question is answered by moderation. All types of exercise can be damaging if done to excess or just trying to do too much too soon. Start out small. Use low jumps until your body becomes adapted for balance and timing. Unfortunately the stories come from people just not willing to give their body a break, rest in between workouts and vary their workouts. Running everyday is not good either. Unless you have joint problems, Plyometrics is as safe as any other exercise and provides another area of physical training.

``````````````````````````````````````````````````````````````````

Lower Body Plyometrics by Les Archer

When you take a good hard look at sportsmen and women training in the gym, you will find that nearly all of their time is spend on upper body or ( Upper ) lower body exercises. This means that the chest, shoulders, hamstrings, glutes and quads get worked over well. You will not find someone that goes to gym and trains his or her lower legs and feet exclusively. It always forms part of some program or circuit. This area is seriously neglected. If you consider that you spend a lot of your time on your feet running, walking or just standing about, is it not time that you take a bit more care of your lower legs and feet?

I believe that of you take a bit of time out of your normal routine and spend it wisely on your lower legs and feet, you will gain plenty. Plyometrics is a well known concept and practiced by many coaches and trainers. I further believe that plyometric jumps should not be done unless a sound lower base program has been followed. By doing this your lower legs will be stronger and you will be less injury prone.

This is a lower strengthening program done without weights, and your plyometric jumps will improve as you will be able to do more and at a higher intensity as your lower legs will be able to withstand the forces better. In the end you will become more powerful not only on the fields but you will feel the benefits in the gym as well.

Normal warm up routine to be done prior to this training session, with a bit more focus on the lower leg.

If you have never done this type of work, start off on 15m and add 5m every 3 or 4 week. I will not exceed 30m per exercise.

Week 1 and 2: 2 sets per exercise

Week 3 and 4: Add 5m or add 1 set per exercise

Week 5 and 6: 3\4 sets per exercise and add 5 m to the distance

Week 7 and further. Just add distance until you've reached 30m. I recommend not more than 3 sets per exercise.

Rest is normal walk back after every effort.

Different jumps:

Note: Every time your feet leave the ground, lift your toes up into the dorsi flexed position before you strike the ground again.

Forward jumps

1. Two legged with small steps and feet facing forward.

2. Two legged with small steps and feet inverted or turned inwards.

3. Two legged with small steps and feet turned outwards or everted.

4. Two legged diamond jumps. ( On your toes, with feet turned inwards so that your toes touch. Jump forward and turn your feet outwards so that your heels touch still staying on your toes. Jump forward into the starting position )

The same can be done backwards or with one leg.

Lateral jumps

1. Two legged to the left and then to the right with feet facing forward.

2. Two legged with feet inverted in both directions.

3. Two legged with feet everted in both directions.

4. 180° jumps in a lateral line. ( Start of with feet facing forward. Jump up and to your left making a 180° turn and land facing in the opposite from what you started off. Next jump the same but turn to the right. ) Continue with this until you reach the marked distance.

5. One legged for the very advanced athletes. Same jumps as in the lateral jumps but with one leg.

After eight weeks of training on this program you will find that you will move better s a runner and as a gym fanatic your stronger lower leg will give you more balance with your standing weights training. This program will also help players in events where they are required to be agile or quick off the mark as in soccer, football, rugby, ext.

Les Archer - Speed and conditioning coach Cats super rugby and Lions rugby Track and field, sprints and jumps international coach +27 82 429 7310 or les @ glru.co.za South Africa