The depth jump is a great vertical jump exercise when used correctly within a good vertical jump program, but as jump coach and VerticalJumping.com contributor Joel Smith discovered, there are actually a few different varieties you can use to drive even better results.
You see Joel recently completed some scientific research on the depth jump were he examined the regular depth jump, and compared this to a depth jump over a hurdle and a depth jump to an overhead target. For clarity I have made a short video demonstrating and discussing the different versions he tested and compared.
Joel was kind enough to answer a few questions about his study for me and here are his (excellent) responses.
VerticalJumping.com: In the study you found that the depth jump to a target resulted in longer GCT but higher jumps and the hurdle variety resulted in shorter GCT. From a training perspective what sort of practical applications do these findings have?
Joel Smith: Well, in the study I actually found out that the hurdle jump resulted in a faster speed of the center of mass at toe off as well (which should lead to a higher jump) but that doesn't entirely make sense, because in theory you should get higher jumping for a target. Regardless, I think the use of both type of goals is really important in building a well rounded program. It is just like weightlifting in a sense, and is lifting light weights fast or heavy weights slow the better method?
Well experts will tell you they both are, and it is the same with the depth jump program. You can use a target overhead for power, and the hurdle will help with your speed at takeoff. I think if you are a team sport athlete, such as basketball or volleyball you would probably want to have a greater percentage of your training jumps be towards some sort of overhead goal or even a specific one (depth jump to dunk) and if you are a track and field athlete or really want to focus on your single leg jump, you might want to focus a little more on using the hurdle.
I will say also that a drawback of my study was that I did not give any sort of instruction whatsoever on how much ground contact time should be spent on the ground, I just wanted each athletes "natural subconscious" reaction to each stimulus. A point of interest is that one of my subjects, Daniel Beck had a ground contact time of around .4s on each of his jumps, yet he was by far the highest jumper.
I wonder what would have happened if I would have instructed the subjects for minimal ground contact time on all jumps. Most likely a version of what actually happened in my study, but you can certainly use an overhead goal and minimize your ground contact time if you actually focus on it.
Finally a cool aspect of my study that doesn't get quite as much attention I feel, is that during the hurdle jump, knee flexion was also less, and there was a greater torque moment and power in the ankles and hip joints, particularly the ankles. This is part of the reason I think that hurdle hops are so popular among track and field athletes, as there are incredible torque moments required of the ankle joint during the track and field jumps. A former Swedish athlete of mine used to do an excessive amount of hurdle hops in his practices over in Sweden in high school and he always noticed a lot of soreness in his Achilles tendons following those workouts. Makes sense.
VerticalJumping.com: With the hurdle depth jump version do you think there would be much difference between using that exercise versus just performing a series of hurdle jumps in a row? Obviously the depth jump version has a higher eccentric stimulus per jump if you step off a reasonably high box, but multiple hurdle jumps still provide a reasonable level of eccentric stress, particularly if you use high hurdles. For example like to use hurdle jumps with 75cm hurdles which would seem to be a more efficient way to train for lower GCT.
Joel Smith: Good question. I use both variants in training, and there are actually probably hundreds of combinations you can come up with regarding depth jumps and hurdles. I will usually use one of three variations when I use hurdles in training. The first is the straight depth jump over one hurdle. The second is performing consecutive hops over 4 hurdles put very high, for me, up to 50" (this is my best, and I have got 3 over 52"). The third variation I like is to use 8 low hurdles (around 30") and just go for really low contact times to try and groove that low contact pattern as well as correct posture and knee alignment. I think when you are trying to train the body for lower ground contact time, it is not just the CNS at play but also the way the muscle-tendon structure interacts, so a few more reps are good here.
I like to use the multiple response hops more in the preparatory periods and move towards the single response as we move into specific training. As I move to the single response, I'll usually start the box around 18" when we start, and move up about 6" a week in box height, unless the athletes are struggling with their landings.
I have gotten great results from all three variations, although when I first started with my "Christmas program" about 3 years ago, I was getting awesome results from just using the 4 hurdle hop method, and wasn't really doing any single response depth jumps for that year. The next training year, however, I was using all three variations, and a ton of single response jumps, and was really getting up there... head to the rim off one leg, and I could clear a 56" hurdle off a 24" box.
You can also do variations such as a depth jump over a hurdle, and then follow that up with 2-4 hurdles. Another one I like is to jump 2 low hurdles and then one really high hurdle, and make it competitive. Finally.... single leg hurdle hops are an AWESOME exercise for a one leg jumper. The forces on the hip and ankle are put to extremely high levels. It was one of my staple exercises the year I went from a 6'8 to 7'0 high jump in competition.
VerticalJumping.com: Looking at the overhead target version of the depth jump, do you think there is much scope for the use of overhead goals in other training drills?
I personally believe that a goal will lead your jumps to be higher. There are plenty of variations you could create, but as I mentioned before, I think you should try and make your goal in depth jumping as close as possible to what you are trying to accomplish in real life. For the vast majority of us, that means dunking a basketball, so if you can find a hoop with an adjustable rim, you are in luck! Unless of course your hops are nasty enough to dunk on a ten foot rim off a depth jump, which I would love to see someone do (maybe I can get it myself here soon, and post a video). Goals increase your effort level, and I think that a specific goal such as a basketball rim might increase it even more.
Depth jumps are one of the best vertical jump exercises but only when programmed correctly in appropriate volumes, within the context of a properly structured workout, and just as importantly, when prescribed for an athlete who can actually benefit from performing them (not everyone needs to do depth jumps).
When programmed poorly with too high a volume, and no considerations given to the individual athlete you can end up just pounding your joints with little vertical jump gain.
So how do you know if you need to perform depth jumps, and how many sets and reps should you do? The easiest way is to get us to work it out for you. You see our vertical jump program includes an individual assessment of your strengths and weaknesses and also fully customised jump training programs to ensure you are only doing exercises that will provide you with the optimal results from your training.
As a result you get more gains on your vertical jump in less time. Click Here to find out more.
For those of you who are interested in finding out more about Joels work the full study was published in the January issue of the NSCA's Journal of Strength & Conditioning Research, however I have posted the abstract below for you to get a better understanding of what the research involved.
Kinematic and Kinetic Variations Among Three Depth Jump Conditions in Male NCAA Division III Athletes
Smith, Joel P1,2; Kernozek, Thomas W1,3; Kline, Dennis E2; Wright, Glenn A2
Journal of Strength & Conditioning Research: January 2011 - Volume 25 - Issue 1 - pp 94-102
Our purpose was to provide an in-depth investigation of 2 commonly used depth jump variants: depth jumping over a hurdle and depth jumping while touching as high as possible using an overhead goal. Fourteen male athletes performed a series of depth jumps from a 45-cm box. Three types of jumping conditions were used. One type of depth jump was a control jump (DJ45-C), performed for maximal height with no external apparatus used to influence the jump. Another type of depth jump was performed over a hurdle (DJ45-H), which was set at an individualized height for each athlete based on their leaping ability. The final type of depth jump was performed for maximal touch height on a Vertec measuring device (DJ45-T).
Timing, kinematics, and kinetics of the 3 jumping conditions were compared. The hurdle depth jumping condition demonstrated lower ground contact times and significantly less (p < 0.05) flexion in the hips (41.22 ± 8.10 degrees) and knees (67.47 ± 8.36 degrees) when compared to control (49.26 ± 10.90 degrees of hip flexion and 73.85 ± 10.68 degrees of knee flexion) and target (50.51 ± 9.51 degrees of hip flexion and 75.01 ± 9.97 degrees of knee flexion) conditions. Jumping conditions that used goals (DJ45-H, DJ45-T) produced significantly higher (p < 0.05) vertical velocity of the sacrum at toe-off (3.57 ± .34 m/s and 3.46 ± .36 m/s, respectively) than the control condition (3.32 ± .34 m/s).
The hurdle depth jump condition had higher ground reaction forces (875.36 ± 135.66 N) and higher dorsiflexion (566.02 ± 402.45 W) and plantar flexion power (768.84 ± 192.19 W) at the ankle than the Vertec (409.83 ± 387.23 W for dorsiflexion and 622.54 ± 188.95 W for plantar flexion) and control conditions (425.60 ± 380.01 W for dorsiflexion and 643.35 ± 166.70 W for plantar flexion).
Few differences were found to exist between the Vertec and control conditions. Hurdle jumping in particular may be superior for the development of short ground contact time (<0.3 s) sport movements requiring brief but powerful lower-extremity power production.
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