Vertical Jump: Genetics or Training?

“That’s the first dunk I’ve ever seen from an 8th grader,” the loudspeaker bellowed out across the gymnasium at the annual middle school Battle for Route 50 basketball game. I couldn’t help but smile.

All three of my teenage sons have very good verticals (30”+). One of my sons has a particularly exceptional vertical jump. Combine that with the fact that he is tall for his age, has reasonably long arms, isn’t yet in high school, and that makes his jumping ability a common talking point at basketball and football games. Many people know I am a trainer and a strength coach, and I have been surprised how many people have asked me, “Is a good vertical from training or genetics?”

Honestly, I was sort of surprised by the framing of the question the first time someone asked me, and I brushed it off. Then several other people asked me essentially the same thing. Then I proceeded to witness a debate among basketball coaches on this topic, and I felt the responses were lacking. Thus, this article was born.

Defining Genetics and Training

Before we delve into the debate, it’s important to settle on the operational definitions of the terms we are using, so everyone is speaking essentially the same language.

Genetics is the study of heredity and the variation of inherited characteristics. Your genes come from your parents, and when most people say something is a result of genetics, they are implying that it was predetermined, and there is little or nothing one could do to alter this trait. Height and eye color are good examples of traits that are considered completely or very strongly determined by genetics.

When we talk about genetics and sports performance, we have to go one step further. In my experience, people are really talking about one of two things when they are using genetics to explain sporting ability. These two things are not the same, and we need to know the difference between them:

• Genetic Starting Point (GSP) – This represents a child or an adult’s baseline natural, normal growth, and physical development. This is the level of development and ability one would achieve without any external training, coaching, playing any formal sports, or other intentional physical activity.
• Genetic Maximum Potential (GMP) – This represents an individual’s maximum physical ability if they did everything perfectly in regard to training, nutrition, etc. This is an individual’s ceiling in terms of what they are capable of achieving.

Training is an intentional activity designed to improve one or more aspects of physical fitness or sports performance.

Is Vertical Jump a Function of Genetics or Training?

Let’s return to the original question. Is one’s ability to vertical jump a function of genetics or training?

First, let’s take an extreme example. If one’s vertical jump was 100% a function of genetics, then that would mean that no form of training of any kind would have any impact on one’s vertical. Hopefully, if you have any familiarity with physical training, you realize that isn’t true. Indeed, if jumping ability was 100% determined by genetics, then that would mean that every variable that affects jumping ability would also have to be determined by genetics. These variables are listed below. Hopefully, everyone can agree that bodyweight has an impact on jumping ability (put on a 50 lb vest and then see how that affects your maximum vertical), and hopefully, no one feels that their bodyweight is 100% determined by genetics.

On the flip side, if someone makes the claim the vertical jump is 100% explained by training, this position is equally false. This would imply several things. First, it would imply that every person who has never performed any training should have a 0” for their vertical jump, and we know that isn’t true. It should also imply that all groups of individuals who undergo the same training plan (for example, 50 recruits who go through boot camp) should all have the exact same response to that training plan, and again, common sense and science (the principle of individual variation) tell us that is not correct. Finally, it should be obvious that certain things which affect one’s vertical jump are indeed primarily genetic, for example, limb length. Having very short legs is a huge negative if the goal is to have a high vertical jump. Little People will not have very high vertical jumps compared to NBA players, and it should be obvious that training alone will not equal out that situation.

Now we know that one’s vertical jump is not 100% determined by genetics and it is not 100% determined by training; this is not an either/or situation and that framework is not helpful for understanding what is happening. However, we don’t want to fall down the trap of attempting to assign percentages, for example suggesting that one’s vertical is 60% genetics and 40% training – that isn’t very helpful either.

To get a better understanding of what is going on we need to return to our definitions. First, everyone will have their own genetic starting point and to be explicit, this genetic starting point will vary among different individuals. Unfortunately, babies do not come with a little attachment that has all of their genetic starting points listed for you. We don’t know for sure what someone’s genetic starting point is, however, we can look at averages and get a pretty good idea and we can test individuals and do a bit of reverse engineering and get an ever better idea.

Next, we want to apply any training to that genetic starting point. Assuming the training was effective, it will now improve one’s ability beyond their genetic starting point. Training can improve the ability all the way up to one’s genetic potential. Again, we don’t know exactly what one’s individual genetic potential is, but we can still provide an educated guess.

Finally, if we are looking at one’s performance on a specific event on a specific day, we need to investigate if there are any variables, acute or chronic, that might be affecting one’s performance at that point in time. Examples include but are not limited to: fatigue; injury; health status; mental state; time of day; environment; level of psychic arousal, etc. Generally, these variables are more likely to take away from one’s maximal ability as opposed to improve it, although the latter is possible.

The accompanying figure above tries to help visually explain how this process works.

First, we are looking at three individuals: Person A, Person B, and Person C. Each individual’s genetic starting point is marked with a yellow vertical line; each individual’s genetic maximum potential is marked with a blue vertical line. Thus, their general range of ability will fall between their starting point and their maximum potential as marked by the black horizontal slightly curved line.

The person’s current jumping ability is marked by a brown X; for example, that might represent their most recent score on a vertical jump test. Then you will see two triangles under that X. The blue triangle is smaller, and it pushes slightly beyond their current ability. These are immediate factors that might improve performance, for example, offering someone $1000 if they beat their old score, or performing the test in front of a large group of people cheering for you. The red triangle is larger, and it represents potential impacting factors that would decrease one’s current performance, for example, doing a very tough leg workout and then having to do the vertical jump test right after would cause a poor performance. A twisted ankle, a bad back, etc., would all negatively affect performance. These factors also have the ability to quite significantly affect performance. The goal is to minimize any of the red factors and try to maximize any of the blue factors.

If we look at specifics, Person A has an extremely high vertical jump of 38”. They had a genetic starting point of 24” and a genetic maximum potential of 43”. Training has added about 14” to their vertical jump, and it might be able to add another 5”. It is possible that they might be able to improve on their current best through psych motivation, ideal warm-ups, etc., up to about 41”. It is also possible negative factors could impact their jump, perhaps severely, even bringing it down below 10” in extreme cases.

Person B has an above-average vertical jump of 25”. They had a genetic starting point of 17” and a genetic potential of 30”. It is possible that they might be able to improve on their current best through psych motivation, ideal warm-ups, etc., up to about 27”. It is also possible negative factors could impact their jump, perhaps severely, even bringing it down below 10” in extreme cases.

Person C has a below-average vertical jump of 14”. They had a genetic starting point of 10” and a genetic potential of 18.5”. It is possible that they might be able to improve on their current best through psych motivation, ideal warm-ups, etc., up to about 16”. It is also possible negative factors could impact their jump, perhaps severely, even bringing it down below 5” in extreme cases.

Key Variables that Affect the Vertical Jump

Physiological Variable	Controllable/Non-Controllable	Most affected by Genetics/Training
Morphological Factors: Limb Length, Tendon Insertion, Fiber type/arrangement	Non-Controllable	Genetics
Form/Technique	Controllable	Training
Bodyweight	Controllable	Training
Muscle Development*: Glutes, Quads, Hamstrings, Erectors, Calves, Core, Shoulders, Arms	Controllable	Training
Rate of Force Development	Somewhat controllable	Training

*Not an exhaustive list

As we can see from the above chart, some factors are heavily influenced by genetics while many other factors are heavily influenced by training.

Hopefully, we are now much better able to answer the question: Is one’s vertical jump due to genetics or training? To which we would respond it is not an either/or question. One’s genetics will provide a natural starting point which will vary among individuals and also a maximum genetic potential which will also vary among individuals. Training has the ability to increase one’s vertical jump from the genetic starting point up along the continuum up until one reaches their maximum genetic potential. And finally, many factors can affect a specific vertical jump performed at a specific time and place, sometimes boosting one’s ability, often decreasing one’s ability.

Training the Vertical Jump

Most of my readers are into working out and lifting weights, and since we just established that one can have a very significant influence on vertical jumping ability through training, the next logical question is: what are some of the best exercises to improve your vertical? Here’s a list of exercises I would suggest you focus on:

Optimal Exercises to Improve Vertical Jump

Exercises for Power	Exercises for Strength
Clean	High Bar Squat
Snatch	Trap Bar Deadlift
Trap Bar Jump	Conventional Deadlift
Box Jump	Leg Press
Broad Jump	Bulgarian Split Squat
Triple Jump	Romanian Deadlift

If I had to pick just one exercise, it would be the clean. I personally believe the hang clean to be the most beneficial, and from a movement point of view, it mimics a vertical jump the closest. If your goal is to improve your vertical jump, I would encourage athletes to really focus on the jumping part of the clean. I know not all Olympic Weight Lifters perform the lift that way— their goal is to lift as much weight as possible in the clean; our goal is to use the clean to build explosive power and jumping ability, hence we want to emphasize the jump. I don’t think it is any coincidence that my son who could dunk in 8th grade could also comfortably hang clean 225.

You should be able to do a pretty quick assessment of yourself and see if you are lacking more power or strength. If your jumping ability is already pretty good but you are pretty thin and you aren’t lifting much weight in the “strength” exercises then you will likely benefit from improving your strength. If your strength is high but your jumping ability isn’t, then you should focus much more on the power exercises and jumping in general. Since many of my readers are powerlifters, ironically the sport of powerlifting is much better at building strength than power, so the normal powerlifter is strong enough but often needs more work on power to be a good jumper. On the flip side, teens are almost never strong enough. They will want to be focusing on a combo of both strength and power, but ensuring they get plenty of strength work.

It is also important to mention that bodyweight has a huge impact on one’s vertical. Vertical jump is a relative strength ability; relative strength refers to how strong you are compared to how much you weigh. Super heavyweight squatters don’t typically have good verticals because even though they have tons of strength and decent absolute power, they typically have poor relative strength. Football wide receivers, DBs, and running backs generally have good relative strength, so visualize an athlete who looks like that – lean and strong. Having a reasonable amount of muscle is good (although looking like a pro bodybuilder is not), having excess fat is not. If one is overweight, dropping the excess pounds will be the quickest and most effective way to improve one’s vertical jump.

These Concepts Apply to More than just Jumping

One of the reasons I wanted to write this article is because this approach can be very useful when examining almost all physical abilities and components of fitness. Don’t think of an ability as being all genetics or all training. Instead, use what we have learned here. Each person will have a genetic starting point in strength, cardiovascular endurance, bodyfat, flexibility, power, speed, agility, etc. Each person will also have their own genetic maximum potential in those categories. And then training and nutrition will have an impact on those abilities.

Physical abilities which have a smaller window between one’s genetic starting point and genetic maximum potential are often thought of as “genetic” abilities, but as we have seen here, that is not the best way to describe them. Maximum speed, for example, is often considered highly genetic because the window of ability is moderately small. For example, imagine there were 200 kids in middle school, and they all ran a 60-yard dash. If you took the 100th place kid and trained him for a year, it is still unlikely that he would be the best or even top 5, even if those other kids didn’t train. However, he would still get noticeably faster compared to himself, thus training would have improved his genetic starting point, but it might not be enough to overtake someone else’s genetic starting point with no training. Usain Bolt, for example, would probably have been faster than 99.9% of the population even with no training, but he would not have won the gold medal without any training. And many people with lots of training would never be as fast as he was without any training.

Strength, on the other hand, has a much larger window. You still have a genetic starting point, you still have a genetic maximum potential, but generally, the difference between the two is very great, and in the vast majority of instances, a person’s genetic maximum potential for strength will be higher than someone’s genetic starting point for the same sex. Take the bench press, for example. My genetic starting point for the bench press was probably around 100 lbs. My genetic maximum potential was probably a bit over 400 lbs. That is a very large difference. If we go back to someone running a sprint, you can train very hard for a long time and hope to take 2 seconds off of your 100M time (which is about a 10-20% difference in performance). With strength, there was a 400% difference!

Something that is very important to mention is just because someone’s genetic starting point is higher than someone else’s in a certain ability, that does not automatically mean that their genetic maximum potential is higher. Let’s look at Jennifer Thompson, one of the best female bench pressers in the world, as an example. When I interviewed her, she told me that when she first started out, benching 65 lbs was heavy for her. She went on to bench press an amazing 320 lbs! It is very possible that another person might have started out comfortably benching 85 lbs (thus having a higher genetic starting point), but her genetic maximum potential might have been 180 lbs. And you can only really know what your genetic maximum potential is if you spend your life trying to get there. Estimates are useful, but certainly, sometimes they will miss the mark.

My hope is after reading this article you have a better understanding of the variables and factors that affect the vertical jump. You will understand that athletes will have a genetic starting point and a genetic maximum potential. You’ll understand that training and nutrition are the main ways to progress from your genetic starting point up to your genetic maximum potential. You’ll understand there are factors that can and will affect a specific performance at a specific point in time, occasionally boosting performance but more often than not decreasing performance. You’ll understand that you need a combination of strength and power to jump high, and you can access which one a person needs to focus on the most. And you’ll understand the best exercises to incorporate into your program if your goal is to improve your vertical jump. If you can remember most of that, my job is complete.

Good luck in your pursuit of a jaw-dropping vertical!