Mechanics and Development of Single Leg Vertical Jumping

Mechanics and Development of Single Leg Vertical Jumping By Joel P. Smith, MS, CSCS, USATF I

Cover By Jake Clark

Introduction This report is designed to be an extensive resource regarding the development of single leg leaping ability. Athletes from all disciplines will be able to benefit from the contents within. This report will also prove incredibly useful to track and field coaches as a biomechanical reference and training toolbox for those athletes involved in the jumping events of track and field. The four parts of this report are as follows. I hope you enjoy the information, and that this takes you to the next level of your athletic performance! Chapters

Part I: Overview of Jumping Biomechanics Part II: Elements of Single Leg Jumping Part III: Physical Qualities of a Single Leg Jumper Part IV: Exercises for Single Leg Jumping Developmen

Part I – An Overview of Jumping Biomechanics

Exhibit A: James White

This report is designed to give you, as an athlete, a more in depth view of how to improve your single leg vertical jumping ability. It is designed for a variety of readers; the athlete proficient at jumping off of two legs who struggles off one, the athlete who is already good off of one, but wishes to get better, a track and field jumper, or a coach hungry for new information. Jumping off of one leg can be tricky business, especially if your body is not really used to doing it. Many athletes want to have that pop off of one leg that allows them to get up quickly on a fast break in basketball to throw a nasty dunk down with authority. Despite their desire to do so, many athletes who are good at jumping off of two legs will just struggle getting up at all off of one leg and find themselves frustrated as to why they aren’t good at it. To help remedy this scenario, this article is designed to be a comprehensive resource in terms of what exactly goes into being a good single leg jumper. Being a track and field coach, I have worked with a lot of natural two leg jumpers and have been assessed with the task of turning them into one leg jumpers for the sake or long and triple jump. I feel that my experience with biomechanics in graduate school, my education on how track coaches teach the motor learning progression of single leg jumping, and then my own experience training two leg jumpers into one leg jumpers has given me a nice working knowledge of how to help any aspiring athlete increase their vertical off of one leg. I feel that there are three basic reasons that athletes tend either have or do not have single leg jumping

ability. These three reasons are: biomechanics/technique, muscle-tendon stiffness and motor learning/practice. This article will go into each of these topics in depth, but in a way that is easy to read and understand. Exercises designed to assist these factors will be given at the end of the report. If you don’t want to get into too much heavy reading, I have summarized the main technical points of jumping at the end of part II. Part IV is going to be where many of the corrective exercises for vertical jump off of one leg will be found, but in order to reap the maximal benefit regarding the increase of your one leg jump, you will want to at least scan through the entire report. The biomechanical factors of single leg jumping will be the first aspect covered. If you are someone reading this who just feels awkward when performing a single leg jump, this section will help you learn what the final product should work in getting up off of a single leg. Even if you feel your single leg jump technique is pretty sound, you still can benefit from a better knowledge of the exact biomechanical contributions to a good one leg jump. Finally, for any track and field coaches reading this, many of the concepts will be familiar, but you may find some concepts you were unaware of, and how to optimize the unilateral jump.

Track coaches can use these principles to optimize their athlete’s technique and power

Single leg jumping on the basic level is actually more dependant on technique rather than just raw power. It is typically a skill that most athletes either seem to have or do not have. It is not all that hard to turn a natural one leg jumper into a two leg jumper through strength training methods, but doing the reverse, turning a natural two leg jumper into someone good at jumping off of one can be a difficult process. Although complicated, jumping off of one leg helps athletes to take serious advantage of the horizontal speed that they can generate, and then turn that speed into vertical velocity. Jumping off of one foot is a more efficient way for athletes to convert speed into vertical than jumping off of two feet, and often can be used to reach vertical leaps well into the 30’s and sometimes 40’s without having the large amounts of strength or power that their two leg jumping counterparts might have. So how exactly does single leg jumping work? Well first let’s look at the basic principle that is a must for any athlete to get of the ground regardless of one or two leg jumping style. Lowering the Center of Gravity

No matter what your natural jumping style is: one or two legs, or even in a standing jump; you must lower your center of gravity (COG) in order to propel yourself upwards. In case you didn’t know, your COG is an imaginary point just a few inches below your belly button and in the center of your body, it represents the one point in your body where you would be perfectly balanced if it was suspended from an imaginary string.

The center circle represents the COG

It is not possible to jump up without first bringing the COG downwards. Like Newton’s Law states, for every action there must be an equal and opposite reaction. If you don’t believe me, then try this: Stand completely upright and see how high you can jump without bending your arms, back, legs or hips down at all…. just try and jump without first moving downwards by bending your hips, knees, and ankles. It probably was not very high, maybe a couple of inches at best. In order to jump high, any athlete must learn to optimally lower their COG.

Once the COG is lowered, there are two basic methods that an athlete can use to raise it up and achieve liftoff. The first way that athletes can achieve vertical displacement is through the power of the athletes muscles themselves. A standing vertical jump is a prime example of this. During a standing vertical effort, an athlete will lower their center of mass through the bending of the hips, knees and ankles. Since there is no momentum brought into the jump (other than the rapid lowering of the body which puts the stretch shortening cycle into effect and provides some loading on the tendons), it is primarily up to the power of the muscles to provide the force needed to get the athlete up in the air. It is for this reason that big squats in the weight room tend to equal pretty big standing vertical jumps. More muscle power output means more vertical in this scenario. Don’t get me wrong, having some serious power is pretty important for single leg jumping as well, but the correlation isn’t quite as direct, you can have the power, but be unable to use it in a single leg vertical attempt.

The second way that an athlete can get vertical is to use their body limbs as rigid levers in order to convert horizontal speed to vertical speed. In the early years of athletics, track and field pole vaulters used completely stiff poles in the pole vault event to launch themselves over a bar over 15 feet in the air.

Old School Pole Vaulting

During running jumps, and especially during a running single leg jump, your leg is the pole! It converts the speed of your run-up into vertical. Look at the following pictures of two athletes in the plant phase of their jumps and you will see just what I am talking about.

Running Double Leg Takeoff

Running Single Leg High Jump

When looking at these jumps we can deduce a few aspects of running jumping in general: 1. The athletes must position their limbs out in front of their center of mass to form the “lever” system which will give them vertical velocity. If you plant under (not in front of) your center of mass when preparing to jump, you are not going to project your body on much of a vertical angle (you will jump more out instead), unless your run-up is extremely slow. The faster you are running, the farther you will have to plant out in front of your center of mass to travel upwards. 2. Athletes proficient at running jumps will lower their center of mass prior to takeoff. Different athletes will lower their bodies by different amounts according to the eccentric loading they can handle and the design of their muscle tendon structure. There isn’t an optimal amount of lowering for all athletes across the board. 3. The knees of these athletes are not nearly bent to the point they would be if they were performing standing vertical jumps, they are much more rigid. The knees bend minimally because the athletes need to conserve the speed of their run-up when taking it to vertical. If the knees bend too much, the “lever” which the athlete is creating to get themselves vertical is now more of a noodle (even if it is a strong noodle) and won’t help convert horizontal speed very well. Compare the factors that are involved in a running jump with a standing vertical jump. They are different motor skills. Here is a video of the levers involved in a standing vertical jump. Notice how much greater knee bend is present in the standing vertical jump vs. the running vertical jumps.

Standing Vertical Jump

Some athletes are physically built to perform running vertical jumps better than others. For single leg jumps especially, long legs in relation to torso are very beneficial, because this increases the length of the lever system in the jump. Another genetic factor that is going to determine the ability of an athlete to be successful in running jumps is the structure of their Achilles tendon. Research by Earp and colleagues (2011) showed some eye opening results regarding how the length of the Achilles tendon affects how force is produced and transmitted in the lower leg. Earp found that athletes who have shorter Achilles

tendons will tend to do poorly when jumping from a standing position, but will be more powerful when performing elastic jumping, such as a depth jump. Athletes with shorter Achilles tendons will tend to do better respectively with jumps from a running start, and the more speed brought into the jump, the better. On the other hand, athletes who have extremely long Achilles tendons will do very well in their standing vertical leaps, but suffer when a running start is involved. I can personally attest to this research as seen this in my own athletes, and I will provide two examples below. A few years ago, I coached a girl (who was also the NCAA DIII national champion in the 55m dash) who had extremely long Achilles tendons and hit a 30.8” standing vertical off of my just jump mat. She could not manage any better jump height from a run-up. Conversely, I had a Swedish jumper recently with extremely short Achilles tendons. He managed only a 25 inch standing vertical jump, but yet he long jumped close to 23 feet (7 meters), and he was not all that fast either (11.75-11.80 in the 100m dash). You can also look at the legs of Stefan Holm and discover the same thing….short Achilles, a poor standing vertical (only around 24”) and a HUGE running vertical jump. His short Achilles tendon allows for a brief, but powerful loading of force and makes his leg an effective rigid lever which propels him insanely high in a running vertical jump. The ultimate build for a running vertical jump off of one leg is one with a thin frame, very long legs and short Achilles tendons. Check out videos of world class high jumpers, and you will see what I mean.

Andrey Silnov: Explosive, Thin, Long Femur, Short Achilles = Single Leg Jump Machine!

Now, just because you might lack the genetics to clear a high jump bar 2.30 meters over your own head doesn’t mean that you can’t improve your single leg jump! Simply having the correct biomechanics in a unilateral jump will help any athlete out immensely. In part II, I will break down the single leg jump into five primary components, and then discuss the exact actions that need to occur for an athlete to really get up off one leg. The five points are summarized as follows: 1. 2. 3. 4. 5.

Lowering the center of gravity in preparation to jump The rhythm of the last few steps A positive push of the penultimate leg A negative pull of the rigid takeoff leg A powerful drive knee of the swing leg

Part II – Five Elements of Single Leg Jumping We will now go into detail regarding each phase of the single leg jump. First, let’s talk about the lowering of the COG in the single leg jump. The following diagram shows the path of an athlete and their center of mass as they prepare to takeoff in a single leg jump.

Notice that in the last 2-3 steps before the plant, the athlete will lower their center of gravity down a few inches which allows the takeoff leg to be set up in front of the body and create the lever system which will promptly send it skyward. It is important to realize that some athletes will lower their center of gravity more than others. Athletes who are stronger in the weight room and who tend to have a bit more power or cross sectional muscle area may lower themselves a bit more than thinner, speed-based athletes who can’t manage a whole lot more than their bodyweight in a parallel squat. Even amongst elite high jump athletes there is a significant range in how much the center of mass is lowered at the takeoff. Lowering the center of mass is important, but in order to do it correctly, a certain rhythm must be acquired. Athletes that can jump very well off of one leg will have this takeoff rhythm built into their subconscious. Track coaches will often refer to the last two steps in a unilateral jump as a “quick-quick” or “flat-flat” rhythm (we will get into the whole “flat-flat” concept later). The rhythm of the last three steps has also been referred to as a “Day To-Day” (speed of annunciating the syllables) format. You could also look at it as: 1..2,3! The rhythm of the last step also involves the takeoff step being shorter than normal. The last step is typically shortened as a result of the athlete lowering their center of mass prior to takeoff. In addition to a fast last step, the rhythm/attitude of the last several steps in general need to be ones of aggressiveness and acceleration. In a single leg jump (or even a running double leg jump for that matter) one needs to run and accelerate into the plant. Slowing down on the last couple steps, especially the final step (the plant), will cause a pretty severe loss in total jump height because it breaks the rhythm of the takeoff. Perhaps the simplest cues for an athlete to consider in a single leg jump are to lower their hips just a bit over the course of their third to last and second to last strides, and then keep the last step quick. This is done all while accelerating into the takeoff; making the last step too long and slow is a recipe for disaster… this being the cause of many missed dunks and failed high jump attempts. The rhythm of these steps should develop over time, and when it is learned, it will tend to become very aggressive in elite one leg jumpers, particularly track and field high jumpers.

On a final note, while it is important to have good acceleration into a one leg jump, when going for maximal height, it is possible to run too fast. If you go into a single leg jump for height all out with a big run up, you may find that your speed is just a little too much to control. What will tend to happen during a takeoff with too much speed is that the knee will buckle from excessive eccentric loading on the quadriceps muscle group. Performing a single leg jump from a 3 step approach is a nice drill to learn the single leg jump, but it is a different skill than doing a single leg jump from a 10-15 step run-up at high speeds. Because of this, it is important to learn what your body can and can’t handle in terms of final takeoff speed, and also to practice your jumping from different lengths of approaches (we will get to this later in the application section). Penultimate Leg Action Breaking the single leg jump down even further, we can take a look at the action of the penultimate leg in a single leg takeoff. The “penultimate leg” refers to the second to last step in a single leg jump. If you jump off your right leg, then your left leg on the second to last step will be your “penultimate leg”. The penultimate step will be initiated by the heel driving towards the ground, and the foot in a dorsi-flexed position (toe pointing up), and land the foot directly under the body. Athletes should be taught to lower their body as a whole during this phase in both a forward and downward direction (forward especially when trying to conserve speed and achieve any horizontal distance in the jump). Although bringing the foot directly under the body is what the athlete should be thinking of when performing the penultimate step, the foot will actually touch down slightly in front of the body. Here is a picture of what the initiation of this second to last step looks like.

Penultimate Step: Dorsiflex the Ankle

As you can see from the picture, the athlete is pointing his toe upwards (dorsiflexion) and driving the heel down towards the ground to initiate the penultimate step. The penultimate leg does two main things to help prepare the body in a single leg jump.

1. Bend the knee joint a bit more than normal to help with the final lowering of the center of gravity (remember, the center of gravity needs to be lowered in order to go up). The picture below illustrates the lowering that occurs during the penultimate step. Notice how the penultimate leg is planted with a significant knee bend and slightly ahead of the center of mass. During this phase, you will notice how the athlete’s hips are lowered to a significantly greater degree than during normal upright running.

Penultimate Step

2. In addition to lowering the COG, the penultimate leg will also provide a “forward push” onto the plant leg. This forward push leads to a very active takeoff rather than a passive one. As was mentioned before, expert single leg jumpers are very proficient at keeping their acceleration up through their plant in the takeoff. The picture below helps serve as an illustration as to how this works.

As you can see from the picture above, the penultimate leg is pushing forwards off the toe to maintain speed into the plant before the athlete jumps to clear the hurdle. Losing speed into the plant will also tend to put the body in a bad takeoff position and shift the loading of the plant leg more onto the knee and the quadriceps group rather than the hips. This will result in a buckling of the takeoff leg. Key Point:

The body is in the most powerful position when the takeoff leg is fairly straight and the majority of the force involved in the jump is absorbed through the hips. Performing the penultimate step correctly is vital to getting a good knee drive when you get into the next phase of the jump. In many skill related activities, especially those in track and field, many coaches look at the particulars of a certain phase of movement, and don’t understand that it is often the preceding movement in the kinetic chain that leads athletes to that point. When the penultimate step is performed correctly, the penultimate leg will slightly lag behind the body of the athlete and load itself up in an elastic manner. Upon the plant of the jump, the leg can snap forward and deliver a powerful knee drive in addition to the planting action of the takeoff leg. This leads us to the next aspect of a single leg jump which is the action of the plant leg. Plant Leg The final phase in setting up the single leg jump is the action of the plant leg. If everything has gone correctly so far, the action of the lead leg should happen smoothly. There are two key points to consider when it comes to the action of the plant leg.

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Pulling the plant leg down in a quick sweeping action towards the ground rather than a push from below. 

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Minimizing the amount of knee bend to form the strongest lever possible (different athletes will have different amounts of optimal knee bend, and it is unwise/unsafe to plant on a locked out knee, but generally speaking, knee bend should be reduced as much as possible). 

When putting together all phases of the jump, the rhythm in the last two steps in the jump is something like “push---pull-plant”! What many athletes who have trouble jumping of one leg cannot seem to do is perform the pulling action of their plant leg; to them it is usually more of a push, or push-push-plant and then a poor and awkward looking vertical display! Illustrated below is a stick figure of an athlete performing a single leg jump with an incorrect plant leg.

Different athletes will have different amounts of bend and foot placement depending on their strength and anthropometrics (limb and tendon lengths). Light and fast athletes with short Achilles tendons will naturally have very little bend in their legs. Heavier and more powerful jumpers will run a bit slower and have a little more knee bend in their jump to allow themselves to use more of their power generated by their large muscles. Knee bend in the plant leg is also affected by the length of the Achilles tendon of the athlete. Those with longer Achilles tendons will tend to utilize greater knee bends in order to “load up” their tendon, while athletes with shorter Achilles will tend to have less of a knee bend and take advantage of the rebounding effect of a short and stiff tendon. The following video is part of a series comparing the jumping styles of high jumpers Donald Thomas and Stefan Holm. Thomas has long Achilles tendons, while Holms are very short. As a result, Thomas will naturally have a greater knee bend than Holm.

http://www.youtube.com/watch?v=_iQbKfd1AfU The last two steps in a single leg jump (penultimate and final step) should both hit the ground flat. What this means is that the athlete should not be trying to jump off of their toe or the ball of the foot. Although sometimes a takeoff where the heels never hit the ground will happen with strong two leg jumpers, it will never be possible in a single leg jump due to significantly higher forces on the ankle joint and lower leg. Although people who tend to walk on the balls of their feet tend to be good single leg jumpers, this does not mean that the plant of the jumps also occurs entirely off the ball of the foot.

Athletes who attempt to plant a single leg jump on their toe will find that their heel will be forced to the ground very quickly (and thus bring about a massive loss in elastic energy)! The forces in a single leg jump are very high and the only way the leg can form a truly efficient lever system is with a flat foot driven plant. Planting on the toe will usually cause the lever to “mush” down under the force of the body and its momentum. In addition to the plant leg, the penultimate (second to last step) in a single leg jump is typically given the recommendation of coming down flat. This advice is given to help the athlete in remembering to lower their center of mass, but a great single leg jump can also be performed without the penultimate coming down flat. “Quick-quick” can be a better cue for the last couple of steps. Posture in the Plant When an athlete plants in a single leg jump, their body posture is crucial to the effectiveness of the takeoff. In order to accommodate the lever system and speed of the jump, the torso should be straight up and down or sometimes slightly backwards. A critical mistake that an athlete could make in a single leg jump would be to takeoff with the torso in a forward lean. In a track and field high jump, the torso is aligned behind the hips and this actually forms a straight backwards lever from head to toe as indicated by the picture below

Anna Chicherova demonstrates the backwards “lever action” that is present in a track and field high jump

(and most other single leg jumps) For other running jumps, such as a running dunk on a fast break, the torso doesn’t have to have a huge amount of backwards lean, nor should it but there should never really be any forward lean of the torso.

Tom Chambers exhibits a slight backwards torso lean in his famous dunk

Knee Drive at Takeoff The final aspect of a good single leg jump is a powerful and effective knee drive. In a single leg jump, the action of the driving knee contributes greatly to the vertical velocity of the movement. Try this simple exercise to see just how high the contribution is:

Knee Drive Exercise: Perform a regular standing vertical jump off of one leg against the wall or under a basketball hoop and see how high you could touch. Don’t think about anything except for how high you can touch. Now try the same thing and don’t allow your non-jumping knee to drive up; make it stays down by your jumping leg. How high did you jump compared to your first jump? Perhaps half as high… if you did well! When an athlete plants on a single leg to take off, the swing leg comes through quickly and “blocks” when it reaches a position around parallel or higher, at least this is the optimal situation; many athletes drive knees do not reach parallel when they are jumping, and coincidentally, these athletes tend not to have very good jumps off of one leg. The drive knee needs to only come up much farther than parallel, however. If it drives up to the chest, for example, this is actually too much, and will cause the jump height to be less overall. The reason why is driving too far would decrease jump height is because, when the knee stops, (also called a “block” by track coaches) it adds its momentum to the jump. If the knee never stops, or doesn’t stop on time in the kinetic chain, it can never add it’s momentum to the jump. Often times, many coaches will actually suggest an athlete driving their knee hard, and then not realize that the athlete is actually blocking too late, or not really blocking…. and taking away from their total jump height.

To get the picture of the effect of a “block” in terms of momentum transfer, try this drill. Sit on the ground with your legs out in front of you and your back straight. Swing your arms upwards with the goal of trying to lift your body off the ground a few inches. You will have to swing as hard as your can for this to happen. Notice where your arms “stop” in this movement, it should be when your upper arms are about parallel to the ground. Now try the drill by just letting your arms swing all the way in the air without stopping them. How high did you get? When athletes keep driving their lead knee too far past parallel without attention to the blocking action (as they are sometimes improperly advised to by track coaches) they will actually take away from their jump. It is important for athletes to make sure they are stopping their drive knee at slightly past parallel to maximize their single leg jump! Part of the reason that it is important to have a good drive knee in a single leg jump is to attain a higher center of mass at the point of takeoff. As far as physics goes, total jump height is a product of: 1. Vertical velocity at toe-off 2. Vertical position at toe-off Vertical velocity at toe-off is simple, it is the speed that your body is traveling when your toe leaves the ground in a jump. More powerful athletes with better technique will have greater vertical velocity at toeoff than their lower level counterparts. The vertical position at toe off is that of the center of gravity. Having a better knee drive will raise the center of gravity in the athlete by a couple of inches. In addition to getting the drive knee up off the ground, it is also important to shrug the shoulders upwards and bring the arms above the level of the head at the point of takeoff. When an athlete does this, they will raise their center of mass a couple of inches higher than it normally sits. Typically, the center of your bodies mass rests just below the belly button, but it can be raised through

the effective use of the arms, shoulder and drive knee mentioned above. Although the concept of raising ones center of mass at takeoff helping vertical jump may seem a little hard to understand, the picture below will attempt to make things more clear.

In addition to the above picture, here is a side by side comparison of three jumpers at toe-off, the one on the left having the highest one leg jump, and the one on the right having the lowest overall jump. Notice the difference in limb positioning at the point of takeoff, and the jumper whose limbs are highest vs. those whose limbs are the lowest.

With this in mind, let’s put all this information together. These points allow us to see a picture sequence of what all goes into a good single leg jump. The following picture sequences highlight the differences between skilled single leg takeoffs and unskilled ones. Take a video and check out your own jump, which one looks more like you?

Tyler (400m runner in track and field): Low skill in single leg jump (30”+ Standing VJ however)

Jake (Javelin Thrower): Moderate skill in single leg jumping

Joel (High Jumper) High skill in single leg jumping

If your current single leg jumping looks like the first series of slides, you have your work cut out for you, but you can definitely still improve your leap off of a single leg! This concludes part II of this article on the single leg jump. By reading this first section, you will have a good idea of why you may or may not currently excel at single leg jumping. If you are not good at getting up off one leg, it is nice to know the theory of how things should look, but you also need to know the best path to take to get better! The second part of this article will be dedicated to how muscle stiffness plays a role in a single leg jump, and then drills and exercises that can be done to improve both biomechanics and leg stiffness. No matter what your current single leg ability is, you can get better! All the information above was fairly long winded and perhaps a bit difficult to all take in at once, so here is a summary of what we went over: 

Athletes must lower their center of mass when jumping in order to achieve any sort of vertical liftoff. In a single leg jump this lowering typically happens over the course of the final three steps. 

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Any running jump, whether off of one leg or two is based on using the legs as levers to convert the athlete’s horizontal velocity into vertical velocity, similar to how a pole vaulter uses a pole to lift their body several meters into the air. A one leg uses this lever system to a greater extent than a running two foot jump. 

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Athletes of differing builds will have their own optimal way of jumping, so one cannot put all athletes into one “box” regarding how to properly configure ones limbs in a single leg jump. 

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Some athletes are also simply built to perform running jumps better than others, and regarding single leg jumps, the length of the Achilles tendon is a critical factor in how the jump is performed. 

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The second to last step in a single leg takeoff is the penultimate step. It should have a little greater knee bend (to help keep the COG low) and be devoted to providing a solid forward  “push” onto the plant leg. 

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The last step, or plant step, in a single leg jump should “pull” downwards and land fairly straight. 

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The plant should be driven off the flat of the foot. Athletes who cannot manage to pull their plant leg downwards but instead “push” it, will tend to focus too much energy on their knee joint, lose the rigid takeoff lever, and thus, not jump very high. 

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The driving knee in a single leg jump massively contributes to the total upward lift in a single leg takeoff. It should stop or “block” when it reaches a position of parallel to the ground. If it does not reach parallel, or goes past it when it stops, energy will be lost in the jump. 

Part III - Physical Qualities of a One Leg Jumper In Part I and II of this series, the biomechanical qualities that allow an athlete to get up off one leg were discussed in detail. Section III is designed to teach the physical quality of jumping that backs the biomechanical action of the takeoff leg, which is muscle-tendon stiffness. In the end of the article, part IV will show some of the best plyometrics, drills, and lifts available that can be used to increase ones single leg jumping ability. A good single leg jumper needs to excel at having high muscle-tendon stiffness in relation to their bodyweight, particularly in the hips, knee, and ankle joints. Creating high amounts of stiffness in the takeoff leg is created through more than just strength found in the weightroom. Within a single leg takeoff, the leg must absorb up to 10x the athletes bodyweight or more. The ability of the takeoff leg to absorb up these great forces is based on ability of the muscle and tendons to act together to produce an extremely brief, but very high amount of tension and stiffness. Check out the following video to see some massive impact forces that are present in a single leg jump.

http://www.youtube.com/watch?v=b4ivgEW5GRo&feature=related The muscle action that is present in this particular movement is actually that of an “explosive isometric” type, rather than a standard “eccentric-isometric-concentric” motion seen in weightlifting. What really happens in a single leg jump is that the muscles will contract hard isometrically; i.e. they lock up. When the muscles lock up, the tendons will go through the stretch shortening cycle of lengthening and contracting, while the muscles keep a similar length. Considering the extreme forces present in vertical jumps, this is the only way that the muscles can sustain the forces of the jump. Concentric motion of muscle is the weakest of the three phases, while the eccentric/isometric phases are much stronger and can handle these high forces for a brief instant. This whole motion is very much

different than weightlifting, so one cannot rely heavily on weightlifting to directly enhance these types of dynamic movements (although weightlifting can certainly help in long term development). The joint which requires the greatest amount of stiffness in the single leg jump is the ankle joint. Research has shown that the less knee flexion and ground contact time that is present in a jump, the higher the impact forces that exist on the ankle joint. When you consider that world “height over head jumped” record holder Stefan Holm has Achilles tendons that are 4x stiffer than the average human being, you will realize that this is no mistake! Single leg jumpers have been said to be “forefoot dominant”athletes. They tend to walk more on their toes and have a little bit of bounce to their step. This is not because those athletes plant on their toe when they jump (because they don’t) but more so because constantly pressuring their Achilles tendon and improving its level of stiffness. By actively engaging the forefoot in dynamic activity, these athletes also wills well as increase the amount of power they transmit through their glutes and hips. As such, it can be helpful to do a large amount of barefoot style training to learn to activate the forefoot more if you are lacking in that area.

Vibram Five-Fingers: A great way to train “barefoot” and build power off your forefoot

Just performing squats and deadlifts cannot fully develop these high levels of muscular stiffness. If you disagree, just take a minute to look at the builds of world class high jumpers. These athletes are tremendously thin and don’t look like they belong anywhere near a powerlifting meet (although in reality, many of them actually have pretty good squats in relation to their bodyweight, although they are never going to win a lifting competition. It is also important to know, that even though those athletes can usually squat a good deal of weight, squatting heavy isn’t what got most of them to that point, they are just tremendously explosive athletes, and even doing things like hill running and plyometrics will drive up their squat) In order to become a truly effective single leg jumper, elastic training needs to make up a large part of your workouts.

Two powerful athletes: Total body speed/stiffness vs. heavy muscle power

Bodyweight Factors in Single Leg Jumping When considering the stiffness of the takeoff leg in a single leg jump, it is important to take bodyweight into account. Although there are exceptions here and there, a general rule of thumb in one vs. two leg jumping is that lighter athletes will tend to be better single leg jumpers, while heavier and more muscular athletes will be more suited towards the two legged jump. Here are some sample builds of recent world champion high jumpers: 6’0, 155lbs, 6’6, 190lbs, 5’11, 150lbs, 6’4, 180lbs. The faster the jump, the more the frame of the body and muscle-tendon action is relied upon. If you are really looking to build up your single leg jump, and you may have some extra pounds, you need to seriously consider losing some weight to really get up there off of one leg. This applies mainly to track and field competitors who don’t have to worry about jumping off of two legs, but if your bodyfat % is a bit high, you will certainly want to lose some weight, nobody wants to jump in a “10lb vest of bodyfat”. In some cases, this will also mean watching how much upper-body work you are doing, if you want to really excel in single leg jumping. Not all athletes are prone to a lot of upper body mass development, but it can cause issues for some.

Olympic high jumpers: Not always a factory of muscle….

The weight of an athlete will influence the run-up speed of the jump. Heavier athletes who are adept at jumping off of one leg will tend to do a little better with a slower run-up, while lighter athletes will typically do better with faster run-ups (optimal run up speed depends on the length of their Achilles tendons as well). Lighter athletes tend to do better at speed oriented, single leg jumping for the following reason: High force/high speed takeoffs rely on the strength that the body can develop in .2 tenths of a second or less in relation to that athletes bodyweight. When a light athlete plants for a one leg jump with a very straight/rigid takeoff leg, that straight lever can handle a very large amount of force! In the case of a single leg jump, large amounts of muscle mass are not nearly as important as an efficient and powerful amount of muscle mass performing an explosive-isometric contraction and producing massive amounts of muscle tendon stiffness in a very short period of time.

The practice pyramid The primary forms of training that will aid the physical properties of single leg jumping are those of direct practice, speed, and plyometric based work. Direct practice is usually the most important area to focus on

and refers to actually jumping off of one leg for maximal height or doing drills that can break down the pieces of the single leg jump and make it more efficient. Speed work refers to sprints on flat surfaces or hills. Run-up speed can be important in running jumps, as well as the ability to accelerate quickly into the takeoff. When it comes to training the high jump in track and field, speed is an essential quality that needs to be improved throughout the year. There are certain speed standards that are typically assumed for certain levels of performance in a single leg high jump. Finally, plyometrics are a vital ingredient in developing a powerful one leg jump. Plyometrics provide a direct way to train the specific “explosive isometric” muscle contraction that is relied on so heavily in a fast single leg jump. Starting early, practice makes perfect.

Let’s talk about how direct practice and motor learning are of great importance when considering the one legged jump. Perhaps the most important reason efficient single leg jumpers are good at that skill is because they learned to jump that way from when they were young. Science has proven that it takes around 10,000 repetitions of a particular motor skill before mastery of it can be achieved. Athletes who started practicing jumping off of one leg early in their lives will have a huge advantage over those athletes who have not! Also, even those athletes who are pretty good at jumping off of one leg will usually be fairly mediocre at jumping off their off leg, because they have not practiced the motor coordination of jumping off of the other side of their body! For comparisons sake, imagine hardly ever practicing, or not learning how to sprint until you were perhaps 15,16 or 17 years old? How far behind your peers do you think you would be in this case? Would you ever be able to really catch up? You would be able to catch up a little certainly, but since neural pathways are really developed at a young age, it is important to get that ball rolling in an athletes early years. In my own experience, I learned how to jump off of one foot around age 10 when a classmate suggested I might be able to jump higher that way. I tried it and found it to be quite effective, I could just an inch or so higher using that method at the time (yes, I have a good memory). Ever since that point I was hooked and was constantly trying to jump as high as I could at my school to touch lights/beams etc. When I had reached age 14 I could dunk miniature and deflated basketballs off of one leg, but yet I could barely touch the rim jumping off of two feet. My practice of the one leg technique had allowed me to achieve a good level of mastery in that area after several years of practice.

A young Stefan Holm gains an early start on his jumping career

Plyometrics complimented by strength training provide the backbone of a good single leg jumping development program. There are a multitude of plyometric exercises that are available to athletes to help them increase their single leg leaping ability. Great basic exercises to help develop the elastic quality of the muscle tendon complex would involve submaximal plyometric exercises such as tuck jumps, squat

jumps, line hops, skater hops, pike jumps, and any other low intensity hopping exercise where the ground contact time is fairly low. Athletes should aim to become proficient at these exercises prior to moving on to more advanced exercises such as bounding, depth jumps, and hurdle hops, especially younger athletes or those without much prior training. Once an athlete does reach a high level, improving ones skill at more advanced plyometrics will really help to increase the stiffness of the ankle, knee and hip joints and will start to cause single leg jumps to feel fairly effortless.

On top of plyometrics, one of the final keys to becoming truly proficient at single leg jumping is becoming more of a forefoot dominant athlete and having massive amount of stiffness in the lower leg and ankles. You can typically tell a forefoot dominant athlete as one who seems to bounce along as they walk or run. Their heels barely touch the ground! Because they have built up this particular habit of walking, they have amassed a high amount of stiffness, and their Achilles tendons are going to take more force to compress than someone who is much more heel dominant. Many track coaches will assign barefooted warm-ups for the reason of building forefoot power (that and injury prevention). My personal favorite modality for this particular aspect of fitness is that of barefoot “rudiment hops”. In this particular drill, the athlete will perform low amplitude hops with a stiff plant leg. This drill is an excellent way to develop power through the forefoot, and will be explained further in video in part IV.

Part IV: Building a Single Leg Jumper The first two parts of this series were devoted to learning about the basic theory and technique of improving single leg jumping ability. This final article of the series gets down to business in regards to the actual exercises that will help you to tie everything together and hopefully put quite a few inches on your single leg running jump! Video sections covered in this final article will include: Plyometrics, Direct Practice Methods, Drills, and Supporting Strength Methods. The following is a list of exercises to help improve single leg vertical leaping. For the sake of this article, it will be assumed that the reader is familiar with simple plyometrics such as tuck jump, squat jumps, line hops etc. Direct Practice (Direct Jumping Coordination): Practicing single leg jumps for height from 3,5, and 10 step approaches 1-2-3 Jump http://www.youtube.com/watch?v=veK0y0HRlj4&feature=channel_video_title 1-2-3Jump over short hurdles http://www.youtube.com/watch?v=ZkUC_Yx3ow&list=UUeVON2SD5dFiqAavFcyC5rw&index=7&feature=plpp_video

Holm Hurdles http://www.youtube.com/watch?v=WVZ3ZcorTF0 Assistive Drills (Jumping Coordination Assistance): Skips for Height http://www.youtube.com/watch?v=qx7qj-Jj1lY Repeating Takeoff http://www.youtube.com/watch?v=lhqJcDzOJWM&feature=related Repeating Takeoff Emphasizing COG Height https://www.youtube.com/watch?v=qxdf8UbgpTc&feature=channel_video_title Center of Gravity Bench Takeoffs http://www.youtube.com/watch?v=gtx11MzBP5Q&feature=related Two Step Knee Drives http://www.youtube.com/watch?v=56MXNjgoZX8&list=UUeVON2SD5dFiqAavFcyC5rw&index=1&feature =plcp

Basic Plyometrics Tuck Jumps Squat Jumps Lunge Jumps Butt Kicker Jumps Stair Runs Low Box to Box Jumps Bench Jumps Cone Hops Line Hops Rudiment Hops http://www.youtube.com/watch?v=lvkQgU7Nr38 Advanced Plyometrics (Stuctural and Motor Recruitment): Bounding http://www.youtube.com/watch?v=0bQuLV1MFSQ Scissor Bounding http://www.youtube.com/watch?v=eci4lO2FhSk&feature=related Hurdle Hops http://www.youtube.com/watch?v=LqsmO4POv7c Single Leg Hurdle Hops http://www.youtube.com/watch?v=re0M7vc3yuU

Depth Jump http://www.youtube.com/watch?v=t1rfTfJ7iDg&feature=plcp&context=C34666c4UDOEgsToPDskLB1mQz tuu3BEKyAMmV-C5B Single Leg Depth Jump http://www.youtube.com/watch?v=Oo9b4rnzz_I&feature=plcp&context=C38269d9UDOEgsToPDskL0iKw UxuWV0uGiz8bkryNj Helpful Strength Training Drills (Maximize Motor Pool and Injury Prevention): Pistol Squat http://www.youtube.com/watch?v=Ji00tONBmZE Explosive Pistol Squat http://www.youtube.com/watch?v=pvUSq9E2STk&list=UUE_HRDp99q7dJ5tWy26HYpg&index=1&feature =plcp Barbell Skip https://www.youtube.com/watch?v=KQP91DSuATs Barbell Step-Up https://www.youtube.com/watch?v=SPFxUsCy7So Barefoot Running/Walking Now this information is all nice, but how can it help you as an athlete? How much can you improve? Well, that really depends on how hard you are willing to work at it and how much time you are willing to invest. If you like the exercises but are not sure exactly how to tie everything together in an organized program, feel free to send me an email. Right now I am perfectly willing to help you out for free as I have the time. You can also check out the free single leg jumping program I have put together which has brought about some great single leg jumping gains even in experienced athletes. http://www.just-fly-sports.com/?p=120 Training really doesn’t have to be all that complicated, in fact, it is really quite simple. Perhaps the simplest way to improve your vertical leap off one leg is to practice 10-20 jumps per day, 5-6 days a week off of one leg from different run ups (with technical considerations in mind), and then pick a few assistance exercises that you enjoy doing or you feel suit your needs. You will pick up the majority of your results from this simple method. Barefoot/forefoot training never hurts either! I am also working on an exciting new vertical jump development book, Vertical Ignition, coming out in 2012. I look forward to hearing from your response to this report! Joel Smith, MS, CSCS

References:

25 Tips for Coaching the Horizontal Jumps. Mike Pullins, Championship Productions, 2007. Baggett, Kelly. "Unscrambling the Puzzle of The 1-leg Jump." Jump Higher, Run Faster, and Perform Better - Enhance Athletic Ability. Web. 19 Dec. 2011. < http://www.higher-faster-sports.com/unilateraljump.html>.

Best of British Track and Field, Coaching the High Jump. Alex “Fuzz” Caan. Championship Productions. 2009. Earp, J. E., R. U. Newton, P. Cormie, and Kraemer J. W. "The Influence of Muscle-Tendon Unit Structure on Rate of Force Development, During the Squat, Countermovement, and Depth Drop Jumps." Journal of Strength and Conditioning Research 25 (2011). Web. Jacoby, Ed, and Bob Fraley. Complete Book of Jumps. Champaign, IL: Human Kinetics, 1995. Print. Nelsen, Roger Jr., Engineering an Athlete. PDF Version. Rogers, Joseph L. USA Track & Field Coaching Manual. Champaign, IL: Human Kinetics, 2000. Print.