"Kinetic energy accumulation training
We will now discuss a special form of strength training that I call ?kinetic energy accumulation training? (or KEAT). It involves training methods in which there is an important kinetic energy build-up during the yielding phase of a movement and the consequent use of this energy to potentiate the overcoming portion of the exercise. This type of training has been known under various names: shock training (in Russian literature), plyometrics (by Western coaches) and powermetrics (a more recent term by Dr. Mel Siff).
I?d rather use the denomination kinetic energy accumulation training as it explains the nature and the reason for effectiveness of this type of exercise. Namely, by increasing the amount of kinetic energy produced during the yielding phase, and transferred into the execution of the overcoming phase, you increase power and force production and you improve the neural, reflex and muscular factors involved in force production.
Most coaches limit this type of exercise to the classic plyometric drills (depth jumps of various kinds) and regular jump training. However many more methods are included in this type of training. Before I present them and explain the reason for the efficacy you must understand that KEAT is basically a form of accentuated eccentric training. However, instead of accentuating the eccentric stress by maximizing eccentric tension (lowering very heavy loads or lowering moderate loads slowly) we are going to use a very fast yielding action. The objective is not to increase eccentric stress, but rather to build-up as much kinetic and elastic energy as we can. To do so, the yielding action must be very fast and the coupling time (time between the yielding and overcoming phase of a movement) must be very short.
The types of exercise that we will include in this category of methods are:
1. Depth jumps
2. Altitude landing
3. Overspeed eccentrics
Depth jumping, also known as shock training, has been developed by Yuri Verkhoshansky in 1977. The objective of this method is to increase concentric power and force output by stimulating the muscles and reflexes via a ?shock stretching? action preceding the overcoming portion of the movement. This is accomplished by dropping from a certain height (0.4m to 0.7m. Heights of up to 1.1m have been used but only by very advanced athletes) to elicit a powerful stretch activation and jumping up as high as possible immediately upon landing.
It has been well established in both Eastern and Western studies that depth jumping, or shock training, can significantly increase power production and the vertical jump. This is mostly due to these factors:
1. An increase in reactive strength. Reactive strength refers to the capacity to rapidly switch from an eccentric/yielding action to a concentric/overcoming action. Lack of reactive strength will lead to a longer coupling time and consequently a lower force and power production during the overcoming portion of the movement (Kurz 2001).
2. Neural adaptations. Viitasalo et al. (1998) have found a different neural response with in athletes doing a lot of jumping and regular individuals when doing a depth jump: jumpers were able to activate more motor units during the movement (greater EMG) and plan the motor command faster (higher and more rapid pre-action EMG). Kyr?l?inen et al. (1991) have also found that 16 weeks of depth jump training led to a better jumping efficiency. Schmidtbleicher (1987 and 1982) found that trained subjects were better able to use the kinetic energy produced during the eccentric portion of a depth jump while in untrained subjects this eccentric period was actually inhibiting instead of potentiating! Finally, Walshe et al. (1998) concluded that the reason for the superiority of depth jumping training over regular jumping was due to ?the attainment of a higher active muscle state?, meaning that the fast eccentric portion of the movement increased muscle activation.
3. Structural adaptations. Depth jumps have been reported to cause some muscle soreness and muscle damage (Horita et al. 1999). This is understandable since the eccentric force production is very high, albeit rapid. So this could indicate that depth jumps are a powerful stimulus to stimulate structural adaptations. Obviously, depth jumps do not lead to significant hypertrophy. So the nature of the structural adaptations following depth jumping is not quantitative in nature but rather qualitative: an improvement of the strength and contractile capacity of each muscle fibers.
Soviet literature gives the following guidelines when practicing depth jumps:
1. The joint position upon landing should be as close as possible to that of an important sport action (Laputin and Oleshko 1982).
2. The amortization phase should be short enough to avoid loosing the elastic energy produced but long enough to allow for the shock stretching to occur (Laputin and Oleshko 1982). Research indicates that the elastic energy from landing is stored for up to 2 seconds. So in theory you have a window of 2 seconds between the landing and take-off phase, However to maximize the training effect, you should not spend more than 1 second on the floor.
3. The height of the drop should be regulated by the preparedness of the athlete: the heels should not touch the ground during the landing phase, if they do the height of the drop is too high (Laputin and Oleshko 1982). A height varying from 0.5 to 0.7 appears to be ideal for most strength and power athletes (Roman 1986).
4. 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 (Laputin and Oleshko 1982). The problem with coaches and athletes is that they do feel that depth jumping is hard: it?s not very tiring compared to other means of training. Because of that they do way too much volume of depth jumps.
5. Still because of the very powerful training effect of depth jumping, it is idiotic to perform this type of training systematically throughout the year. The shock method should be used in blocks of 3-4 weeks with at least 4 weeks between blocks (Roman 1986). In fact some coaches recommend no more than 2-3 such blocks per year (Medvedyev 1996) and that these blocks should only be used when a rapid rise in power and reactive strength is needed to further performance gains. Remember that every training method, regardless of how effective it is, will loose it?s effectiveness over time. Shock training is no different. So if you use it year-round there comes a point where you will get no added benefits from it. However by using short ?shock? blocks you can give a quick boost to your performance and since you only use depth jumps for a short period, everytime that you use such a shock training block you will get the same performance boost.
A recent paper by David Kerin (2002) concluded that it is the eccentric portion of a depth jump that actually has the greatest training effect as far as increasing vertical jump and lower body power. It makes sense when you think about it. It is during the landing portion that the eccentric stress is at its highest as all the kinetic energy accumulated during the fall is transformed into muscle loading. So this can greatly increase your capacity to break your fall and absorb this kinetic energy. If you are weak in the eccentric portion of the depth jump what will happen? The coupling time (time it takes you to switch from yielding to overcoming) will be very high and the resulting jumping capacity will be low. The shorter the coupling time is, the higher will be the subsequent jump. And to reduce coupling time you must increase eccentric strength and the capacity to absorb the kinetic energy.
Depth jumps obviously do this, but doing only the eccentric portion (landing) and practicing ?sticking the landing? (i.e. immediately breaking the downward movement as soon as you hit the ground) can actually be more useful in that regard. And this way you can use higher drop heights (up to 0.75-1.25m). Once again, the key point is to land in a position specific to your sport. For example football linemen and linebackers should stick the landing with the knee bent at approximately 90-110 degrees.
Just like depth jumps, altitude landings have a very powerful training effect and should only be used for short periods of time and at a very low volume of work. While they can sometimes be used in the same training block as depth jumps, I don?t recommend it. Rather I like the following progression:
Block 1 (4 weeks)
Block 2 (4 weeks)
Low intensity jump training
Block 3 (4 weeks)
Block 4 (4 weeks)
Low intensity jump training
This progression will ensure for constant and rapid progress in vertical jumping capacity. You can repeat that 16 weeks cycle three times during the year for fantastic improvements.
This type of exercise could almost be called shock training with weights and it?s the brainchild of powerlifting coach Louie Simmons and is described in his training videos ?Reactive method? and ?Special strengths?.
Simmons explains that to take advantage of eccentric training for maximum strength gains in lifting exercises you should use it (the eccentric/yielding portion) to accumulate kinetic energy that you will transform in elastic energy, reflex energy and ultimately a greater force production in the overcoming portion of the lift.
To do so two things must be present:
1. A fast yielding phase: by lowering the bar or your body faster you produce more kinetic energy. There is actually some research to back up this technique, not that the results from the Westside powerlifting crew doesn?t already speak volume for the its efficacy! For example a study by Farthing and Chilibeck (2003) found that ?eccentric fast training is the most effective for muscle hypertrophy and strength gain?. This is in accordance with the findings of Paddon-Jones et al. (2001) that following a fast eccentric training program led to a decrease in type I fibers (from 53.8% to 39.1%) while type IIb fiber percentage increased (from 5.8% to 12.9%). In contrast, the slow eccentric group did not experience significant changes in muscle fibre type or muscle torque.
2. A rapid switch between the yielding and overcoming phases. The best example of this break in the yielding/overcoming chain is the use of the box squat. When you land on the box you immediately halt the yielding portion of the movement, converting the kinetic energy into elastic energy and reflex action.
One doesn?t have to use the box squat. You can simply lower the bar as fast as you can and break it in a heart beat before lifting it explosively.
Using Jumpstretch elastic bands attached to the bar also have a very positive effect because the bands will actually try to ?blast? the bar down, bringing it down faster than if only gravity was acting on it. This is one benefit that you don?t get from using chains, chains are only acting as additional weight, while the elastic bands increase kinetic energy."