Thursday, April 11, 2013

Plyometric Exercise Guidlines

Guidelines when performing depth jumps:

1.The ground contact (amortization) phase should be short enough to avoid losing the elastic energy produced but long enough to allow for the shock stretching to occur. To

maximize the training effect, you should not spend more than .5 seconds on the floor and less than .2 seconds is much better. Its best when doing plyometrics to think of the ground as a hot skillet.  If you stay down too long your feet will get burned. Plyometrics are very effective, but when increasing maximum power is your goal, they should be
done with concentration and intensity on every repetition and not in a fatigued state or in a high volume per set fashion.  When performance begins to decrease during a set it is time to stop. Much like strength training involving higher repetition sets, doing depth jumps in a high volume fashion dampens recruitment of the FT fibers which is essentially just wasted time unless you are training for endurance.

2. The height of the drop should be regulated so that the heels dont touch the ground during the landing phase.  If they do the height of the drop is too high. A height varying between 18-28 inches appears to be ideal for most strength and power athletes with up to
45-50 inches for advanced athletes.  The distance that you jump away from the box
should be approximately the same distance as the height of the box.  So if you’re jumping off a 36-inch box you should land approximately 36 inches out.  (Zatsiorsky)

3. Depth jumps have a very powerful training effect so the volume of work should be low: no more than 4 sets of 10 repetitions (or 40 total jumps spread over more sets), 2-3 times per week for advanced athletes and 3 sets of 5-8 repetitions (or 15-24 total jumps spread over more sets), 1-2 times per week for lower classes of athletes

4. Because of the very powerful training effect of depth jumping, it is best to avoid performing this type of training constantly throughout the year. For consistent gains these blocks should only be used when a rapid rise in power and reactive strength is needed. Every training method, regardless of how effective it is, will lose its effectiveness over time. Plyometric training is no different. If you use it year-round there comes a point where you will get no added benefits from it. However by using shorter blocks of training of no more then a few weeks, you can give a quick boost to your performance and everytime that you use them you will get a substantial boost.

Guidelines for “shock” or depth drops or jumps:

Remember a shock jump is also called a depth drop and is done when you step off a box and just try to stick” the landing without jumping back up.  The landing portion of a depth jump has a very high training effect when it comes to improving explosive force output and even strength. During the landing portion the stress is at its highest as all the energy accumulated during the fall is transformed into muscle loading (energy absorption training). With each foot contact in a sprint the legs have to absorb forces equivalent to around 5-6 times bodyweight.  With a shock jump the force upon impact can exceed 10 times bodyweight. Specific training in this fashion can greatly increase your capacity to absorb energy. If you are weak in the eccentric (landing) portion of the depth jump what will happen? The amortization phase or coupling time (time it takes you to switch from landing to jumping) will be very long and the resulting jumping capacity will be low.

Before you can put force out in a plyometric movement you have to be able to take force in and gather it.  The more force you’re able to efficiently take in and store, the shorter your amortization phase will tend to be and the more force youll put out, thus the higher your subsequent jump.

Depth jumps do increase absorption strength but shock drops really allow you to zero in on this portion of a plyometric movement.  So, when utilizing shock jumps you will just execute thelanding portion of a depth jump and practice sticking the landing without allowing your heels to hit the ground. You can vary the position as well to zero in on different muscle groups.  Sometimes you may land with straight legs, sometimes you will land in a squat, and sometimes you will land in a lunge.  Regardless of the performance, you will immediately break the downward movement as soon as you hit the ground.  You can also use higher drop heights (up to 30-50 inches). Just make sure you always pay attention to the point at which force created starts to overcome force absorbed. When you land with a loud thud, you’re no longer absorbing the energy efficiently.  Like depth jumps, when executing a drop jump you should land “away from the box about the same distance as the height of the box.

Guidelines for “otherplyometric drills:

Other plyometric drills include various hops, bounds, and jumps that dont have the same extreme landing forces of depth jumps or shock jumps.  Athletes of all ages and classifications can do some form of these drills and they are very effective to use to build an athlete up to being able to tolerate a cycle of more advanced plyometric depth jump or shock jump training.  The intensity and volume can be gradually built up, but just like the more intense versions of plyometrics, one must pay attention to recovery and volume.  I like to do a higher volume of these drills in between cycles of more intense depth jumps and plyometrics and a lower volume during the cycles of depth jumps and shock jumps.
A sample 12-week cycle might look something like this:

Week 1-3:  Higher volume lower and moderate intensity jump training (i.e. single and double leg jumps, hops, skips – depth jumps up to 18 inches)

Week 4-6:  High volume weights + low volume low intensity jump training

Week 7-9:  Moderate volume accelerated weight training (jump squats, speed pulls) +
low volume shock jumps (depth drops)

Week 10-12:  Low volume general weights + high volume depth jumps

In this way one can progress consistently and get the most from their training without burning out on any particular training method.  The workouts Ive designed provide plenty of variety so that people never have to worry about performing the same exercise over and over again!