Drop Jumps and Depth Jumps - Shock Yourself into high gear
By: Kelly Baggett
When you hear the phrase "Russian training secrets" what do you think of? Back in the early 1970's you probably would have waited in anticipation to hear the training secrets that allowed the soviet union to so thoroughly dominate competition in the olympics. Fortunately, now it's 30 years later and the old Russian training secrets have long since been revealed, - but even today that phrase will still set many people on the edge of their seats.
The Russian secret I'd like to talk about and the same one that in large part made the soviets such a dominant force on the world competition scene back in the 70's is called the shock method of training. The shock method consists of 2 very simple exercises that really don't even require any equipment, depth jumps and drop jumps.
Both of these exercises are now commonly lumped into the plyometric family of exercises and were developed by Soviet scientist and coach Yuri Verkhoshansky. The original meaning of the word plyometric (originally spelled pliometric) was intended to mean eccentric contraction.
These exercises rely on forceful eccentric contractions and were used by Soviet coaches as a "shock" method to take speed-strength ability to a new level. The neuromuscular effect is similar to hooking your muscles up to a power plant and injecting them with a very brief high current. In fact, these exercises were credited as being the secret weapon in the training of the great Soviet sprinter Valery Borzov who dominated the 100 meter dash.
Plyometrics became popular in America in the 70s. Soviet sprinters were displaying very impressive sprint times so U.S. coaches decided to go to the Soviet Union to figure out what the Russians were doing. The Americans saw the Soviet athletes stepping off of high boxes, hitting the ground, and jumping back up in the air. Upon their return to the United States, they spread the word of the magic training method and the term "Plyometrics" was coined. Soon all types of leaping and bounding drills were thrown into the same category as the original shock plyometric exericises and before long every coach in the world was using some type of supposed plyometric activity. Unfortunately, they never took into consideration the planning and conditioning that existed in addition to this type of magic training. In the Soviet Union the shock method was used in a cyclic nature which involved varying intensity levels and conditioning methods. Even today many coaches prescribe plyometric exercises without much of a thought of how they should be included in a plan.
How They Work
Recall that Force = Mass x Acceleration.
In normal training, the Mass is increased which leads to static strength development and muscular growth.
With the use of shock plyometrics, the Acceleration is increased which leads to target involuntary neuromuscular and central nervous system processes.
The ultimate goal in shock method training is to maximize the benefits of the stretch shortening cycle or plyometric reflex. You need sufficient strength in the musculoskeletal system before adhering to this type of training. A great deal of force is produced in the joints when performing any type of jumping or falling and one should concentrate on quality training.
Since shock methods increase plyometric capacity and the ability to use the stretch-shortening cycle they are beneficial for virtually any lower body explosive power movement including sprinting, jumping, agility, gymnastics etc. An experiment revealed that a group of track and field jumpers executing primarily depth jumps (all of them did 475 jumps) over a 12 week period showed greater improvement in reactive ability then a group which trained with traditional methods and executed 1472 general pushoffs (squats, squat jumps and hops with 90-95%, 70-80%, and 30-40% of 1rm and a total volume of 93 tons.
To perform a depth jump you stand on a box, step off, hit the ground, and immediately jump up as high as possible at ground contact. You should gain energy from the impact that you absorb, stabilize, and transfer to your muscles and tendons for a more explosive jump.
A drop jump is just the landing portion of a depth jump. You simply step from a box and "stick" the landing.
Although the 2 exercises both increase plyometric power and are very similar they do have a few differences. Nearly all sports movements rely to some extent on plyometric ability. Before you can put energy out you have to take energy in. After you take energy in from one direction you then have to put it out in the opposite direction. The drop jump trains more of the "taking energy in" aspect and the depth jump trains more of the "putting energy out" aspect. Because of this, drop jumps are more of a strength/force movement and depth jumps are more of a rate of force development and speed movement.
Many athletes will train only the takeoff part of a jump, with no concern for building up the capacities needed for a controlled and balanced landing. Athletes should be able to "stick" a landing, absorb the shock, and efficiently transfer that shock into a positive movement immediately.
Testing has revealed that for a shock absorbing landing with a knee bend, athletes use a resistance force 3 to 4 times their body weight. Landing performed with stiff leg joints requires a force of six to 8 times bodyweight. An athlete weighing 132 pounds requires 400 to 500 pounds of force to absorb the shock of landing. The same athlete requires 700 to 1000 lbs to land with the leg joint stiff. When an athlete lands on one leg, as in figure skating, the force at the instant of landing is 3 to 4 times bodyweight for a shock absorbing landing and five to 7 tmes when landing with stiff legs. Dealing with forces like these requires a substantial level of eccentric strength.
Both shock jumps and depth jumps will build up your reactive power which is the ability to generate the force of muscular activity immediately following a landing or the absorption of force. Drop jumps and regular strength training work well to build up plyometric capacity on the max force side of things and build landing strength or the ability to absorb and stabilize force. This trains eccentric strength or the "taking energy in" aspect. Depth jumps work to increase what happens after the force is put into the system, or the "putting energy out" side of things.
Force In vs Force Out
Watch the difference in contact times and the speed at which people change direction from "down" to "up" or from negative contraction to positive contraction when they run, jump, or cut. Depth jumps will shorten ground contact times during the amortization phase (the switch) and improve the rate of force development and velocity that occurs after the transition. Drop jumps will heighten the amount of force we can take in at the transition which will give us more potential to put force out.
So, for someone who's limiting factor is force absorption or strength, drop jumps are a huge benefit. This type of athlete won't be able to change direction quickly because they won't be able to stabilize the negative force to begin with. Think of someone who is the direct opposite of Barry Sanders. For someone who needs speed out of the transition, depth jumps are a better choice. In fact, when it comes to pure speed, a study revealed that the max speed in a sprint correlates best to how much force one can put out in the first .100 (1 tenth of a second) of a depth jump.
If your best vertical jump from a regular standing position is better then your best depth jump from even a very low box height (~ 8 inches) then you should use landings via drop jumps to increase your ability to gather energy and optimize force absorption capabilities. If your depth jumps are higher then your regular standing vertical jump then you are a good candidate for depth jumps. However, nothing is cut and dry here. There is considerable overlap with these training methods so sometimes the drop jump will be used if a person is slow during transition due to inefficiency at absorbing energy.
It has been stated that an athlete should be able to squat 1.5 x times their bodyweight before performing shock plyometrics in order to avoid injury and optimize progress. One thing that must be made clear is that these training methods originally called for box heights of 1 meter or more. When absorbing the force from this type of landing it is necessary to have a high level of strength. Realize you probably won't get much benefit from any plyometric exercises until you have a base level of strength. However, even little kids jump off of playground equipment and furniture all day long without injury. My recommendation is that you should not perform depth jumps from a box height of greater then 18 inches until you can squat 1.5 x or more your bodyweight. However, it is perfectly fine to perform drop jumps from a height equivalent to your best vertical jump regardless of your strength levels. In fact drop jumps combined with general strength training are a great tool to not only increase your eccentric strength and ability to deal with high forces, but also teach basic movement mechanics with force.
Box Height Recommendations
All sorts of box height recommendations are thrown out for depth jumps and the original recommendations called for box heights of .75-1.15 meters. A very simple and effective box height recommendation is to perform your depth jumps from the height of a box that allows you to jump the highest immediately after ground contact. As stated earlier, if you can't perform a depth jump from a box of any height and get up higher then you can in a regular standing jump then you shouldn't be using depth jumps to begin with. One should aim to increase the speed, acceleration, and height of the jump before increasing the drop height. According to the founder of shock method training,Verkhoshansky, you should not spend in excess of 0.2 of a second on the ground after landing.
Drop jumps should be done from a box height that enables you to absorb the most energy without faltering. Aim to "stick" the landing soft and silent on the balls of your feet just like a gymnast doing a dismount. If the heels hit the ground the box is too high and if there is a thud at impact the box is too high. When the box is the correct height the jump should be silent and soft with a reflexive gathering of energy and often a reflexive bounce at impact. When your body is gathering energy efficiently you will feel your system want to reflexively use that energy to advance out of the landing. Generally a good starting point for drop jumps is from a box 20% higher then the best vertical jump and eventually on up to 1.15-1.25 meters.
Both variations of shock training should be performed on a surface that has some give to it to avoid injury. Grass works well as does the use of solid rubber mats. You should land as far away from the box as the box is high. So, if you're standing on a 30-inch box you should land approximately 30 inches away.
When executing depth jumps you should use a simple athletic stance position just as you would whenever you jump.
Drop jump performance can vary. You can land in a regular athletic stance for general carryover, in a stiff-legged stance to emphasize lower leg force production ability, in a 1/2 squat to emphasize the hips and hamstrings, in a split squat stance to emphasize all around balance, and in a 1-legged stance to heighten the magnitude of force absorbed.
The optimal dosage of depth jumps or drop jumps should not exceed 40 combined ground contacts per session for well conditioned athletes and 20 ground contacts per session for lesser conditioned athletes. As a guideline, the dosage of shock plyometrics should not exceed 5-8 repetitions in 1 set and sets of 3-5 work well with up to 30 seconds between reps and up to 10 minutes between sets. Remember that these are a speed-strength tool not an endurance tool. Maximum muscular recruitment requires that you stay fresh. High volumes of consecutive repetitions are not possible or advisable.
Using the above volume shock jumps should be performed once or twice per week in training sessions devoted to specialized speed-strength or strength training.
For best results use the above recommended volumes of shock jumps in short 3-4 week blocks preceeded by a block of higher volume strength training. Another option for someone who already has a great deal of strength is to perform a block of drop jumps in conjunction with strength training, followed by a block of depth jumps and power training, followed by another block of shock jumps with general explosive exercises. The set-up would be performed twice per week and look like this:
Week 1-3 Low level drop jumps/Strength (squat)
Week 4-6 Depth Jumps/Power training (speed squat)
Week 5-7 Drop jumps/General explosive bodyweight exercises
Depth jumping variations give quick results but the gains are just as quick to plateau. Low level variations of drop jumps can be used throughout the year but it's best to really focus on shock training 2-3 times through the year when you need to bring your level of speed-strength to a peak.