The Science of Sports Training

There is a sea of athletic development information on the internet nowadays. The overall quality has improved as more educated people have built websites and social media presence to combat the marketing experts just trying to make a quick buck. That being said there is still plenty of confusion and seemingly conflicting information. One person got a huge vertical by just jumping a lot; another says you have to deadlift heavy; another advocates for various jumping exercises and core strength; so on and so forth. I aim to bring clarity to this discussion through high quality information. Truthfully the human body is complex, so we cannot just assume that one training method will be optimal for everyone. Each athlete is a new puzzle to solve. Some cases are pretty simple and easy, but some are not. And we should not be seeking just any exercise or workout that could work but rather a training approach that is optimal and comprehensive. Jump Science hopes to equip people with knowledge that will help them train intelligently for their entire career or life. Yes, there is a series of training programs available on this site, but I also want people to understand the science behind the training.

Basic Jump Science

The height a projectile flies is determined by the velocity of the center of mass as it leaves the ground. The faster the initial upward velocity, the longer it will take for gravity to decelerate the projectile, and the higher it will travel. In the case of a human jumping, the projectile is the body, and the initial velocity is determined by the acceleration of the center of mass due to the force generated by the body and the time over which that force is applied. Force multiplied by time is impulse. If you want to increase your vertical leap, the goal is to increase the vertical impulse that you push into the ground. Simple enough right? Just lift weights, and your legs will get more forceful, and you will jump higher. This may be true in some cases, but you will likely discover at some point that jump training is not always that simple.

Physical Qualities

The truth is that there are a lot of different physiological abilities that contribute to jumping and all athletic movements for that matter. This article will not get too much into human physiology at the microscopic level, but rather cover six large scale physical qualities that do not require an advanced education to grasp.


In order to jump high or do any athletic movement well, an athlete has to perform it with effective technique. Effective technique is developed through practice. In the case of jumping, the learning process happens largely subconsciously, meaning the athlete does not think about it. Rather the brain figures out the best way to coordinate the movement through repetition. Many great jumpers have never thought about exactly how they jump. This is how babies learn skills like walking and feeding themselves. No one is coaching them. They are not thinking about their technique. They just keep trying, and the brain figures it out.

If proper jumping skill is learned simply through repetition, why do some athletes end up with better or different technique than others? Differences in jumping technique often reflect differences in physical abilities. For example, jumpers with less strength and more explosive and elastic talent tend to use a quick, shallow countermovement in their jumps. An athlete who does not possess those same talents but has great strength benefits from using a deeper, slower countermovement. Some may say this athlete does not have good technique or coordination, but in fact that technique is best for that athlete’s abilities. The correct approach for this athlete is not to consciously alter technique, but rather to work on developing elasticity and explosiveness and continue to practice jumping to allow the brain to adjust jumping technique to utilize those abilities as they change.

The key point is this: to be a great jumper, at some point an athlete needs to build up a history of jumping. Effective technique is acquired through practice. It is not acquired by reading, hearing, or watching ideal jumping technique. People who lack a jumping history may find that they can improve things like flexibility and strength with little transfer to jumping ability. On the other hand, athletes that have built up a sufficient jumping history may find that very little jumping is required to continue having success. How much of a history does one need exactly? That I do not have figured out.

In my experience, it is important that this history of jumping occurs during childhood and adolescence. When adults decide to jump train without having a jumping background, making improvement is far more difficult. Most young children can be encouraged to jump often without concern for safety. After puberty begins, and kids start getting taller and heavier and much more forceful, a more conservative approach to jumping volume (maybe 50 approach jumps per week) is advisable for maintaining quadriceps tendon health.

What about instruction on jumping technique? Beginner jumpers can often benefit from being shown the rough framework for an approach jump. There are also times when a coach can tell an athlete to make a change to a jump, and it produces an immediate improvement. But for every one of those times, there are ten times where making a conscious change makes the jump worse. Thinking about technique during a jump usually has a negative impact. I will not make an extreme sweeping statement like, "Athletes do not need to be coached on jump technique." But I will say that athletes want to get to a point where they are not focused internally on technique but simply jumping as high as possible without thinking.

General Mechanics

Mechanics is a term used in describing movement. It may be used interchangeably with technique, skill, coordination, etc. To distinguish the terms, think of technique as specific mechanics used in one particular movement, and think of general mechanics as characteristics that show up across all movements. High quality general mechanics translate to increased athleticism and reduced injury risk. An example of a characteristic we want to see is the foot, shin, and thigh lining up with each other (roughly) and remaining stable. This might look quite different through the wide spectrum of human movement, but the general principle holds true. What we want to avoid is the foot turning out and rolling in too far and excessive inward collapse of the knee. We develop proper general mechanics with strategies such as gaining appropriate flexibility, building strength and elasticity in the feet and lower leg, mastering fundamental movements like squats and lunges, and adding strength to those movements.


Flexibility is the ability of muscle to lengthen. It is extremely important for athletes for a number of reasons.

  • A short muscle-tendon complex is generally more prone to pain or injury. For example, tightness in the rectus femoris muscle is a common contributor to jumper’s knee.
  • Flexibility has an impact on mechanics. For example, hip extension should contribute a majority of the power for a lot of athletic movements. Powerful hip extension requires hip loading. Proper hip loading cannot occur if the musculature around the hip is too tight, so lack of flexibility means lack of hip power, which decreases athleticism.
  • Lack of flexibility directly inhibits athleticism by resisting high-speed joint movement. For example, the iliacus and psoas muscles (hip flexors) lengthen during hip extension. Tight hip flexors resist fast hip extension, limiting hip power and decreasing athleticism.
  • Flexibility is required for proper training. One thing that has been shown over and over is that strength training with full range of motion has immense value. This is impossible to do without flexibility. For example, a good deep squat position requires large range of motion in the hips. Without flexibility a good squat position cannot be reached, which makes one of the most important exercises less effective.

The importance of flexibility cannot be emphasized enough. Flexibility is gained through the use of full range of motion strength exercises and stretching.


One might think of elasticity as an ability to stretch far like a rubber band. What we want in sports performance is actually the physics concept of an elastic collision, an interaction between two objects in which there is a high restitution of kinetic energy. Think of a bouncy ball bouncing off a hard surface. We want this tpe of interaction with the ground in many sports movements. It is not achieved by stretching far but actually by doing the opposite, keeping the foot and leg more stiff when contacting the ground. Elasticity is largely a structural adaptation to muscles, tendons, and fascia, but the nervous system surely plays a role as well. Jumping itself develops elasticity to some degree, but we can get more by accumulating thousands of quick ground contacts with minimal knee bend. This occurs during upright running and quick hops, jumps, etc.

Another contributor to elasticity is the myotatic stretch reflex. This reflex responds to fast lengthening of muscle fibers by quickly stimulating more tension in that muscle. This enhances all athletic movements, and specifically in jumping it helps an athlete harness more momentum from an approach. The reflex is developed by athletic activity in general, but is specifically targeted by shock plyometrics, which feature drops to the ground at relatively high velocity.


The word strength may be used to refer to force production in general. Here we will use it to refer specifically to maximum strength, the product of the maximum force muscles can produce within a movement. Strength is commonly measured by the amount of weight or other resistance that can be overcome. A measure of strength might be a max squat of 300 pounds. But if measuring strength at the muscular level, an example would be the quadriceps muscles generating 3000 Newtons of force at a given length.

Strength can be broken down into structural and neurological strength. The first refers to the physical structure of muscles, tendons, and fascia. The second refers to neural drive, the collection of nerve signals that stimulates muscles to contract. Think of the brightness of a light. Increasing structural strength is like getting a bigger, better light bulb. Increasing neurological strength is like sending more electrical current to the bulb. Both result in brighter light.

Strength is extremely important for athletes, simply because all movement is driven largely by muscle tension. More muscle tension equals more forceful movement. There is a misconception that explosive movements like sprinting and jumping use different muscle fibers than slower movements like heavy lifting. This is simply false. All movement starts out by recruiting slower, weaker muscle fibers and progresses to recruiting faster, stronger fibers based on the muscle tension required for the task. Heavy lifting requires the most muscle tension, so it recruits the most fibers. So the same muscle fibers used to sprint and jump are used during a heavy lift. Strength training makes those muscle fibers stronger, so they can potentially produce more force during any movement.

There is a disconnect between strength and athleticism, but it has nothing to do using different muscle fiber. It is the result of vastly different movement characteristics. Sprinting, jumping, throwing etc utilize (1) just a short burst of maximum effort, (2) high velocity muscle contraction, and (3) a quick elastic contribution. Because of these differences, jumping and most athletic movements are not displays of strength. But increasing strength is still valuable, because it adds raw capacity to all movements. It is also the best protection against injury.

Strength is trained to some degree by all movement, because all movement uses muscle tension. In particular, anything that involves high effort, such as sprinting and jumping, develops some level of strength. But full range of motion resistance training builds strength to the greatest degree.


Explosiveness is a general term that people use to refer to great athletic ability. In Jump Science vocabulary, it refers to a specific physiological ability, the rate at which muscle tension is generated. Explosiveness is highly complex, as it is influenced by things like muscle architecture, muscle fiber type, and neurological factors. If we could measure at the muscular level, the units would be a percentage of maximal muscle tension per some unit of time. An example would be 50% of max tension in 0.2 seconds. Consider a running vertical jump with a ground contact time of 0.2 seconds on the takeoff plant. Say maximum muscle tension in the quads (in the same position as the vertical jump but in a slow shortening contraction with no time limit) is 300kg. 300kg x (50% per 0.2 sec) = 150kg of muscular force produced during the vertical jump. If training could raise that percentage to 60, the quadriceps force during the jump would go up to 180kg. In actuality muscular force production is far more complex than this, but the point is that producing muscular force faster increases athleticism.

Together strength and explosiveness determine the common sports science term, rate of force development. With this working definition for explosiveness, it is possible to be highly explosive but still have average RFD and athleticism if strength is low.

Jumping itself trains explosiveness for jumping. Other exercises can as well if they have a similar or shorter time frame for producing force. Sprinting and some plyometrics meet this requirement and allow us to train explosiveness for jumping with less knee stress than actually jumping. There are tons of other exercises that may be labeled as explosive, such as medicine ball throws for height or distance, lunge jumps, and power cleans. But the force production window is typically too long on these exercises to actually train explosiveness for approach jumping. Their legitimate purpose is to develop/maintain strength. They can also be used as a power measurement.

Putting it Together

We have these six trainable qualities that influence athleticism. To design optimal athletic development, all these qualities have to be considered, and the training needs to be tailored to the individual strengths and weaknesses of each athlete. It is incorrect to assume that any one type of training will be effective for every person. I will not attempt to diagnose every type of athlete in this article, but I will give a few examples.

Consider an ideal scenario. A talented kid plays lots of games and sports at a young age and instinctively learns how to move well. By the age of 15, he or she possesses pretty good explosiveness and elasticity and has a solid history of jumping. If this athlete begins strength training, there may be dramatic improvement in jumping ability. Increase in strength could come from lifting weights, or in the short term it could even come from some types of plyometrics or other explosive exercises. Either way this is the type of athlete that makes for great testimonials for a jump training program. He or she may gain 6+ inches within a few months. Over time this athlete can reach high levels by continuing to get stronger but keeping the amount of strength training in correct proportion to explosive, elastic activity and possibly even stopping strength training for periods of time.

Now consider someone who is less talented, not structurally sound, and has bad general mechanics. This athlete also needs flexibility and strength training but may not get fast athletic results. More realistically the training will initially help raise the quality of movement and help prevent injury. Athletic progress might be more gradual over time.

On the other hand consider an athlete who has an athletic background but is less gifted explosively and gets into a sport with a strength culture like American football. Strength training ends up being the preferred activity during the teenage years, and by the time he is full grown he squats over double body weight but is still average athletically. Plugging this guy into any strength training system, no matter how ingenious it is, will not yield athletic results. What he needs is explosive training, a large dose of elastic activity, and a drastic reduction or maybe even avoidance of strength training.

Finally consider a guy without much athletic background who decides he wants to dunk in his twenties or thirties. He may find that increasing his lifts dramatically yields only small increase in jumping ability. Addressing flexibility and strength are likely necessary just to keep him healthy, but what is really going to change him athletically is building up a history of elastic activity and jump practice. To be perfectly honest, this is a tough training situation where dramatic results cannot be expected.

Hopefully it is clear that (1) a given training method can produce very different results in different people, (2) different people can gain great jumping ability through very different training, and (3) a method that is effective at one time may not be effective at another time. This is why in my efforts to provide training programs for the masses, it was necessary to design a method people can use to evaluate themselves and then corresponding programs that fit the abilities of each individual. This is far superior to just prescribing common exercises and assuming they will be effective. I encourage you spend time exploring the information on this site. You may find that you are able to design effective training on your own. If you need a training schedule to follow, look into the Jump Science System.