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Firstly, what is a depth jump? A depth jump is a training movement where one starts by standing on a box which can be 12" to 50+" tall and then steps (not jumps) off, free-falling towards the ground. As soon as contact is made with the ground, the athlete rebounds into a vertical jump. This should be done in one fluid motion. Depth jumping is the exercise origin of what we know here in the USA as 'plyometrics'.
This picture is sort of what goes down in a depth jump
The Rules of Depth Jumping According to Joel Smith:
1. Depth jumps have an extremely high training effect. Full recovery from a true depth jumping session can take anywhere from 4 days to 2 weeks depending on the training load and the work capacity of the athlete.
2. Depth jumps should have the number 1 priority in whatever training cycle they are used in. My standard practice when I was in college, as well as is the standard practice in many Eastern Bloc programs is to use plyometrics in a 1 week microcycle where no heavy weightlifting is used, aside from use as a priming exercise. An example of this type of training week would be performing 4 sets of 10 depth jumps from a 35" box on monday and friday mornings. A light weightlifting workout could be administered on monday and friday nights. No workouts with any significant training effects would be used on tuesday, wednesday or thursday.
3. Depth jumps increase your leaping ability in proportion to your strength levels prior to performing them. The prerequisite of having a 2 to 2.5x bodyweight squat before performing plyometrics was NOT a safety issue. I did 1.5 years of true depth jumps barely being able to squat my own body weight and still increased my vertical a significant amount with no injury. The 2.5x bodyweight recommendation is there to maximize the effectiveness of depth jumps in a training cycle. For example, someone who weighs 150lb, has a standing vertical of 27" and can squat 300lb will gain a lot more out of plyometrics than somebody who weighs 150lb, has a 27" standing vertical and can squat 165lb. Many people are aware of this concept.
4. Depth jumps should be performed with some sort of target in mind. Research has shown that jumping towards a target will increase vertical jump heights, as well as change the biomechanics of the jump. If you play basketball, you should do your depth jumps trying to grab the rim, or dunk a basketball on the rebound. If you are a high-jumper, you should also have some sort of target in mind, but this could also include jumping over something, such as a hurdle on the rebound (this is actually what my master's thesis is on). If you play football, have someone toss a football high in the air during the drop and try to catch it on the rebound, etc......
5. Depth jumps, contrary to popular beleif, do not HAVE to be performed on a soft surface (just don't do them on asphalt, at least not for an extended period of time). It really depends on your sport and this is a point where I will be specific to track and field. The softer the surface involved, the longer the coupling time between eccentric and concentric contractions is going to be. If your sport is sand volleyball, well go ahead and do your plyometrics in the sand or on grass. If you are a long jumper or high jumper, however, you should probably be doing your plyometrics on some type of track surface, or even a wooden basketball court (I am speaking for qualified athletes here who don't have biomechanical abnormalities, especially in the feet). If you have 'bad feet', you probably wan't to be more careful of your plyometric surfaces.
6. Effective depth jumping (if you don't want to be waiting 1 week between workouts) should be preceded by few months of GPP work, as well as weightlifting, olympic lifting, submaximal plyometrics, hill running, sprinting, and the like. The year of track and field where I jumped 7', I didn't do any depth jumps until mid-competitive indoor season. (It is interesting to note, I went from a PR of 6'9 to 6'10.25 to almost clearing 7'0.25 within a 3 week period of true plyometric work after having done some great prep work earlier in the year).
7. The optimal height of the box for 2 foot vertical jumping is the maximum height of the box before your vertical starts to decrease. The optimal height of the box to improve one-legged jumping is the maximal height of the box before the vertical starts to decrease PLUS 4-8 inches. These are for 2 leg box jumps. (Note, don't ask me for a reference on this one.......it's a blend of what I have read and what I have experienced over the years) Higher boxes will build reactive strength while lower boxes will build explosive strength. A recommendation for elite jumpers in russia is .75m (30") for explosive strength and 1.1m (44") for reactive strength, but has also been as low as 6" in some american studies with recreation athletes, so the ability of the athlete is a critical factor.
8. Horizontal falling distance should be accounted for in depth jumping. Your vertical target should be placed about 1.5-1.75x the distance of the height of your box away from the bottom of the box. If you were jumping off of a 36" box, your target should be at least 48" away from the bottom of the box. If you dont put your target far enough away, biomechanically, you will be jumping backwards. Unless you play basketball and are used to getting posterized all the time and want to work on your dunk-blocking ability while players are attempting to posterize you, you don't want to work on jumping backwards.
regards,
Joel
(the ultimate self proclaimed vertical jump expert internet guru of the next millenium!) joking!
