How To Correctly Perform and Use Depth Jumps
Depth jumps are what most people (incorrectly) think of when you mention plyometrics and vertical jump training. In training circles many coaches remain unsure about whether the risks outweigh the benefits. In this article I will take a closer look at this often mis-understood exercise and hopefully provide you with some good ideas about how to appropriately use them in your jump training.
WHAT IS A DEPTH JUMPDepth jumps are an excellent exercise to help improve reactive/eccentric strength. One of the great things about them is that often they provide immediate and noticeable gains in jump height. The down side is that these short term results often lead to them being abused as a training tool (see below).
Depth jumps are simply a jump that is performed after the athlete has dropped to the ground off a platform or box. The jump should be both immediate and rapid. As the goal of depth jumps is to improve an athlete's reactive strength, the less bending of the knees and the less time the feet are in contact with the ground, the more effective it is.
A Depth Jump
One of the more commonly heard myths about this exercise is that you should land on your toes and that your heels should not touch the ground. The rationale for this is that your heels touching the ground increases contact time.
This myth is half true. Yes your heels touching the ground may increase contact time, but the landing and jumping can still be performed sufficiently fast so that they provide plenty of reactive strength stimulus. The other upside to a bit of heel contact is that it helps reduce the pressure on your joints by increasing the surface area over which forces can be dissipated.
Another quick point about performing depth jumps is that they are very hard on your CNS. In order to get the most out of them you should make sure you have plenty of rest between sets (2-3 minutes at least). The more reps you perform per set, the more rest you need between sets. You should also get plenty of rest between training sessions. Even with advanced athletes I would still only recommend their use up to twice per week.
SAFETY CONCERNSBefore I continue I wanted to address one of the biggest issues that coaches have with depth jumps – safety. Over the years the abuse of them in an athletes training program has lead to many reporting injuries from their use. Due to this there are a lot of coaches who feel that only advanced athletes should use them (often quoted is the need for a minimum of a 1.5x BW squat).
This however is something that to I do not entirely agree with. Why? I believe it has more to do with the volume and the drop height causing the injuries, not the exercise itself. Look at it this way. No one argues that squats are a great way to build strength in the legs. If you have never squatted before the chances are that you would be pretty bad at it. The squat is also a reasonably advanced exercise. It requires balance, core strength, decent range of motion etc as well as strength.
Does this mean that you wouldn't have a beginner squat? No of course not. What it does mean however is that instead of loading up the bar with 2x your bodyweight you would pick a very light weight to start with and work up from there.
The same approach should be applied to depth jumps. They are a great way to develop reactive strength. Just because you are not great at them to begin with doesn't mean you cannot do them, it just means you have to start nice and easy. In this case nice and easy means starting with a low box and with low number of jumps until you have found a height and volume that allows you to perform the movement quickly, correctly, and most important of all, safely.
DETERMINING DROP HEIGHTThe intensity of the exercise is largely determined by the height from which you drop, and as such the box height (in conjunction with training volume) must be carefully monitored to ensure both safety and effectiveness.
If you use a box height that is too high the obvious problem is an increased chance of injury.
Figure 1 and 2: Choosing the right drop height. When performing depth jumps you need to know your limits. Jumping from too high up can result in some bad crash landings - even for someone as strong as the Hulk!
The other issue related to excessive drop height is that it can create an eccentric (downward) force that is too great for the athlete's reactive strength to handle. So even though the athlete might not injure themselves, the downward force might still be too great for them to overcome quick enough to rebound straight back up and get a decent training effect. Basically, if you step off the box and have to completely regather yourself before you can take off, the box is too high.
So what is an appropriate box height? The most commonly prescribed method is to identify the drop height that allows you to jump the highest when performing a depth jump. The most common method of determining what this height is involves a bit of trial and error.
A simple box height assessment might look like this:
Step 1. Stand on an 12 inch box and perform a depth jump recording the maximum height touched. Step 2. Repeat the process by increasing the box height in 6 inch increments. Step 3. When your jump heights start to decline stop the test.
An example might be:
Test 1 - Height Touched Off 12 inch box: 292cm
Optimal drop height therefore would be a 24 inch box.
What about drop height for single leg depth jumps? The logical answer that comes to mind is to use a box half the height of your two foot depth jump. However, it isn't quite so simple. Landing and jumping with two feet is much easier as two legs make it much easier to balance and minimize the amortization phase.
When you land on a single leg it is much harder for your joints and muscles to absorb the eccentric forces. For single leg depth jumps I would use exactly the same method I just outlined but I would start with a 6 inch box and moveup from there in 3 inch increments instead. You will be surprised how dramatically your performance drops off when using the single leg version.
Single Leg Depth Jumps - Much Harder
Speaking of drop height the next question is when should you start to increase it? Whilst progression is the key to achieving your vertical jump goals, you don't want to do it too quickly, particularly with high impact plyometrics. You should start increasing the box height only after you have made noticeable improvements in your jump height without sacrificing the speed of the jump.
SHOULD DEPTH JUMPS BE USED ALL THE TIMEThe short answer to this is no. One of the great things about this exercise is that often they provide very good gains in a short space of time. However the rate of these gains also tapers off quite quickly. What this leads to is athletes thinking that more is better so they end up doing way too much volume for too long a period of time.
It is this oversuse of depth jumps that I believe has contributed to so many injuries in the past. The length of time you should use them for will once again depend on the height of the box, the volume of jumps performed, and the training experience of the athlete. Once your gains taper off take a break from them for a few months and when you come back you will be ready once again to take advantage of this exercise.
CONCLUSIONDepth jumps can be a very beneficial exercise for improving your vertical jump. They often rate in many coaches top 10 jumping exercises lists. However abuse of them has often resulted in injuries leaving them with a bad reputation with many coaches. Hopefully in this article I have given you some good ideas about how to safely incorporate this interesting exercise into your vertical jump training. The key points are to start conservatively, and to use lower boxes and a low volume of jumps until you start to get a feel for what you can handle.
One final thing, depth jumps are just one exercise out of many you can perform to help you jump higher. While they are certainly very good for developing reactive strength the reality is not everyone needs to use them in their jump training. Some athletes are better off focusing on other areas in their workouts. If you are not sure what areas you need to work in your vertical jump workouts, then you should check out our very affordable coaching service at www.verticaljumping.com/vertical_jump_coaching.html.
This service is more affordable than most jump programs and will produce better results from your training for the simple reason that all the workouts are designed specifically for you. They are 100% customized to your inidividual needs just like working with a coach or trainer in person (only our service is a lot less expensive).
Special Thanks to Alek for letting me use his pictures of the Hulk!. If you click on the appropriately green Hulk link just abovethere are plenty more adventures to see of him getting up to things you might not normally see a giant green monster doing.
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