So you want to increase your vertical off one foot… There are some pretty key differences between unilateral and bilateral jumping you need to be aware of if you’re going to be a one foot jump specialist.
This article is an in-depth look at unilateral jumping, its biomechanics, and how you should train to become better at this style of jumping.
So for all the single leg jumpers out there, I intend for this post to become your bible. Let’s begin!
One Foot Jump Muscle Differences
When comparing the unilateral and bilateral, the vertical jump muscles are involved in very different capacities. It’s important to understand these differences so you know where your focus should be in the weight room, because it’s actually quite different to the two foot jump.
Less Quad Engagement
In the bilateral jump, you see a deep knee bend which really allows us to generate a massive amount of force from our quads. In the unilateral jump, the knee bend is much more minimal and so we’re not using the quads to generate force anywhere near as much.
Quad strength is still important, but it’s primarily to stabilize the knee when planting the jumping foot. We need a smooth and efficient transferral of force from the feet up through to the hips, which requires a sturdy connection from the ankle to the knee.
More Glute Engagement
The hip extensors are far more utilized in the unilateral jump. This is a natural byproduct of having a single point of contact as opposed to two.
You’ll need to make sure your glutes are extremely strong if you’re going to focus on the one foot jump approach.
More Calf Engagement
Again because we’re jumping off a single foot, our ankle extensors are also having to work extremely hard in the single leg jump.
Some suggest that your calves contribute up to 60% of your power in the unilateral jump as opposed to just 15-20% in the bilateral jump, although I was unable to find any research to support this.
Just think about it logically. As you plant your jump foot your calf is immediately heavily engaged right through til toe-off where it’s responsible for that final transferral of force.
More Tibialis Anterior Involvement
I’ve written extensively about the importance of the tibialis anterior in the vertical jump, but it’s so much more pronounced in the unilateral movement.
Research has shown that in jumps with a faster approach speed, the tibialis anterior is doing a lot more work than usual to help stabilize that all-important link between the ankle and knee joints.2https://www.mdpi.com/2076-3417/10/1/309/htm
One Foot Jumper Structural Differences
When we examine elite one foot jumpers, they tend to all have very similar physical characteristics: quite tall, very lean, and narrow hips.
Some people simply gravitate towards jumping off one foot and others are just not cut out for it because they have a body type not particularly suited to this style of jumping. A lot of it is genetic.
If you’re not particularly well configured for the single leg jump, of course you can still improve it, but it’s quite uncommon for someone like this to pursue the single leg approach when they will often jump higher off two feet.
The exception of course is those training specifically for long, high, or triple jump.
Being Taller Helps
If you compare the one foot vertical jump to the sport of pole vault, your leg acts as the pole and is responsible for generating the power to drive you into the air.
Imagine a pole vaulter running into their approach carrying a three foot long pole. That’s simply not going to work.
Longer legs creates more leverage which becomes particularly useful in the single leg jump.
This doesn’t mean you’ll never jump high off one foot unless you’re really tall, just that those who are taller will typically have a slight biomechanical advantage.
Low Body Weight Helps
You just need to take one look at any high jumper ever to see that these single leg specialists are extremely lean. They’re almost always pretty thin and lanky looking.
They also typically have quite narrow hips.
The Exception Of Zion Williamson
I included this section here to give hope to all those guys out there who don’t have narrow hips or aren’t particularly thin and lightweight.
This guy is big. Wide hips, thick thighs and glutes; looks far more like a football player than a basketballer. He weighs over 280lbs, oftentimes not particularly lean at all, and has a 45″ vertical jump.
What’s more amazing is that he absolutely springs off the one foot approach with incredible ease. Most one foot jumpers don’t typically excel at both one and two foot approaches, but Zion is exceptional at both.
Now I’m not saying we can all be great one foot jumpers like Zion, even if we’re not genetically configured for it. What I am saying is that your genetic predisposition isn’t necessarily a life sentence and while it may disadvantage you, it can largely be overcome with enough of the right training.
Stiffer Achilles & Patellar Tendons
When you do enough jumping, the tendons in your legs adapt by getting ‘stiffer’. This sounds like a bad thing but it’s actually this stiffness that helps us create force.
Think of a childrens’ baseball bat made out of a soft foam-like material. When the ball hits the bat, the softness of the material absorbs a lot of the force of the ball and as a result it doesn’t go far. Compare that to a bat you’d see in the major leagues: those things are stiff. You can generate a lot more force with a stiff (or strong) lever than you can with a soft one!
Top high jumpers have been found to have Achilles and patellar tendons much stiffer than normal. This allows them to jump using faster approach speeds and more forceful take offs, as they inherently deal with and generate force better, and can handle and deflect a given amount of force with less knee bend.3Vertical Jump Bible 2, Kelly Baggett
Quicker Ground Contact Time
The stretch shortening cycle of the one foot jump is massively quicker than its bilateral equivalent. The plant foot is in contact with the ground for about 0.8 seconds during a bilateral jump whereas in the unilateral jump it’s closer to 0.15 seconds.
As a result of this we should look to mimic this quick ground contact time when training and this will become one of the primary differences between single leg and two foot jump training. More on that shortly.
Do You Jump Higher Off One Leg Or Two?
There’s no correct answer to this question. The answer is simply, some will jump higher off one foot, and others will jump higher off two feet.
Neither style of jumping is going to lead to higher overall vertical jumps at the top end either. We see elite level verticals off both one and two feet all the time.
What I will say is that not everyone is cut out for the single leg jump and most will typically do a bit better off two feet. This is probably because most people don’t fit into the bucket of people who have the structural characteristics to be well suited to single leg jumping.
One Foot Vertical Jump Technique
There’s a couple of things you ought to be aware of from a technical standpoint if you’re going to practice the single leg vertical jump.
Long Approach At Speed
This style of jumping really lends itself to a longer and quicker approach. Up until a point, the faster your approach, the higher your jump will be. You need to give yourself enough distance in your approach to build up adequate speed.
This is why you don’t see high jumpers approaching from 10-15 feet away – it’s usually three times that distance.
Maintain An Upright Torso
There should be almost no hip flexion as you take off from one foot. Some people make the mistake of ‘diving’ or collapsing their torso forward at the hip joint as they approach the plant sequence.
This is common not only in unilateral jumping but in the bilateral approach also. Avoid this by focusing on keeping your torso nice and upright.
Don’t Forget Arm Swing
This is still a very big part of the single leg vertical jump. A lot of people simply forget to swing their arms aggressively to help generate force upon takeoff.
Make sure you don’t suffer from arm swing amnesia otherwise you’ll be leaving inches on the court!
Training To Increase Your One Foot Jump
There are some specific things we can do differently to hone in on the single leg jump approach. It’s important to remember though that from a strength perspective, specificity isn’t all that important.
If we’re simply training to make our legs stronger, we don’t need to only do unilateral movements. You can and should still do squats and GHRs as these exercises, although bilateral in nature, are still going to help get your legs as strong as possible.
We’ll save the unilateral specific stuff for the speed strength and plyometric work which is where specificity really shines.
Increase Ankle & Knee Extensor Strength
We’re thinking about our plant foot here. We need a super robust connection from the ankle to the knee as we plant that fulcrum in the ground in order to launch our body into the air.
This means you’re going to want to focus on training your calves a lot more than you would in the bilateral jump. The calves (ankle extensors) are extremely involved in the one foot jump and so you need to be working them hard to get them as strong as possible.
Your quads, although they don’t play as much of a power generation role in this style of jumping, are super critical for stabilizing that knee during plant and takeoff.
I mentioned earlier that you will need strong glutes as well. So basically, you need strong calves, quads, and glutes. Basically you need strong legs.
While we need to hit these three major jumping muscles, the order of importance for training will be calves, then glutes, and lastly quads. In the bilateral jump, it’s usually the opposite.
Implement Partial Range Of Motion Exercises
I’m also mentioning this recommendation from Kelly Baggett’s Vertical Jump Bible which is that the single leg jump responds really well to heavy partial range of motion exercises such as half squats and quarter squats.
I couldn’t find data to confirm this but perhaps this has become evident from years of coaching athletes.
So don’t be afraid to plug in some heavy partial ROM squats into your strength sessions!
Unilateral Plyometrics Are Superior
Some research has shown that unilateral plyometrics produce greater results than bilateral plyos do. Not just for the unilateral jump either, but for both types of jumping!
A 2019 study compared the effects of a six week plyometric program where half the participants were given single leg exercises and the other half bilateral. They concluded the following.
Unilateral plyometric training was more effective at increasing both single and double-leg jumping performance, isometric leg press maximal force and RFD when compared to bilateral training.4https://www.researchgate.net/publication/316465763_Comparison_Between_Unilateral_and_Bilateral_Plyometric_Training_on_Single-_and_Double-Leg_Jumping_Performance_and_Strength
This one’s pretty easy to implement. Instead of (or in addition to) doing regular depth jumps, do single leg depth jumps. Instead of bilateral bounding, do single leg bounding.
Best Exercises To Jump Higher Off One Foot?
Below are, I believe, the four ultimate one foot jump exercises. They all build on the above training principles and have a great deal of unilateral specificity.
#1 Single Leg Depth Jumps With Short Ground Contact Time
Pretty self explanatory. Think normal depth jump, except off one leg and much quicker. You’re really looking to explode off the ground immediately upon contact.
You should also use a slightly lower box than you normally would to begin with also.
It will also help if you have another box you can jump onto as opposed to just springing up off the ground on the spot. This will just cushion the landing forces allowing you to focus more on being explosive out of that initial ground contact.
#2 Barbell Step-Ups
These are an excellent unilateral strength exercise that will strengthen the VMO nicely to help protect your knee joint during the single leg jump plant. They also hit your glutes nicely.
You can simply see from how similar this exercise is to the single leg jump how well it’s going to work the relevant muscles.
#3 Single Leg Bounding
Bounding is one of the ultimate plyo exercises and has been used by sprinters and jumpers for decades. The reason it’s so good for the unilateral jump is because IT IS a unilateral jump.
When it comes to plyometrics, specificity is key and so any exercise that gets us really close to actual unilateral max effort jumps are going to be extremely beneficial.
#4 Smith Machine Bulgarian Quarter Split Squats
This is one of the best partial range of motion strength exercises that is safe to do year-round and generates ridiculous amounts of force per leg.
The above image is actually a normal smith machine BSS. The quarter squat variation would simply be going down about half as deep. You’re just trying to make the eccentric portion of the movement as heavy as possible but want to ‘stay above’ of your knee so you’re not having to dig yourself out of a full amortization phase.
Not everyone is structurally configured to be an elite jumper off one foot. Becoming an elite single leg jumper does require more help from genetics than the two foot jump.
Having said that, it most certainly can be improved with proper training. The single leg jump requires more from the posterior chain and also benefits greatly from training in a quicker stretch shortening cycle.
I’m sure by now you’ve learned about the major differences between the unilateral and bilateral jumps and are now far more equipped to target your training to the single leg approach.