Measure jump height, power and velocity – with GymAware

Vertical jumps are a popular exercise to monitor performance and fatigue in a quick and non-invasive way. Since accuracy is highly important when measuring vertical jumps, many practitioners use GymAware to assess jump height, -power and -velocity. This article covers why and how you should measure these metrics.

By Loek Vossen

Measure jump height using GymAware

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Introduction: the vertical jump

A vertical jump is a measure of an athlete’s ability to jump straight up in the air from a standing position. This means that we’re not interested in any horizontal displacement. Even better: there is no horizontal movement during the execution of the jump.

As you can imagine, vertical jump measurements are commonly used in sports such as basketball and volleyball. However, it’s an interesting measure for explosive power and lower-body strength in all sports, including strength training. In fact, it is one of the most commonly used strengths tests to track fitness progress.

Countermovement jump vs Squat jump

At first, a vertical jump seems straightforward, but there are many ways you can jump. When measuring jump performance over time, it’s important to be very specific about the type of jump. Let’s look at two examples.

Counter movement jump (CMJ)

When doing a counter movement jump, the athlete makes a preliminary dip by flexing the knees and hips. He/she then immediately extends upwards to jump vertically off the ground. Such a movement utilizes the ‘stretch-shortening cycle’ (SSC), which maximizes performance through the momentary storage of elastic energy within the joint complex.

Counter Movement Jump (CMJ)
Counter Movement Jump (CMJ)

Squat jump

An alternate type of jump is the squat jump concentric, also known as a static jump. During this exercise, the jumper starts from a stationary semi-squatted position. The jumper does not employ a preliminary downward phase (i.e., a countermovement) and so the jump does not involve pre-stretching of muscles.

Concentric Squat Jump
Concentric Squat Jump

Most athletes can jump 3 – 6 cm higher in a countermovement jump test (CMJ test) than in a squat jump concentric test. So if you test a concentric squat jump, you need to have a very tight protocol to control any eccentric movement prior to jumping. Any eccentric dip will increase jump height a lot, and mess up your data.

GymAware jump power and jump position
GymAware jump power (red) and jump position (blue). In a concentric squat jump, you need to control for eccentric movement (dip).

Benefits of being able to jump high

There are sports in which having a high vertical jump directly impacts performance. Basketball, volleyball but also soccer and American football are some obvious examples.

That doesn’t mean that a good vertical jump is useless if you’re not into those sports. Multiple scientific studies show that your jump performance correlates with leg strength and sprint performance (1,2,3). These traits benefit many athletes.

Moreover, since an explosive jump requires proper signaling from the brain to the muscle, a good vertical jump can be a marker for a well developed neuromuscular system (the way muscle motor units are recruited via the nervous system).

In summary, there are some direct benefits of being able to jump high, but it also indicates other capabilities like strength-, sprint- and neuromuscular performance.

Why you should measure jump height

Performance

If you want to improve performance, it makes sense to track progress. So when your aim is to increase lower-body explosiveness, measuring vertical jump is an interesting way to see if your training program has the desired effect.

There are also a few reasons why you would want to measure jump height that are not performance related. Let’s have a look at some of those

Fatigue

If you want to prevent overtraining, having an objective way to monitor fatigue is important. Regular jump measurements (weekly) have proven to be a valuable indicator of fatigue. You can easily perform the test after a warm up. When the results are below what you would expect based on previous measurements, you can adjust the workout.

The GymAware cloud software helps to track jump height over time, which makes it easier to detect outliers (good or bad).

Talent- and muscle fiber identification

Vertical jump performance is used for talent identification, for instance in swimming. It allows you to get a quick idea of the potential performance of your athletes. 

The (rebound) jump is also used to assess the percentage of fast-twitch muscle fiber distribution, in a non-invasive way. This can be another factor to take into account when looking for talented athletes.

Injury and rehabilitation

Your jump performance can also help to identify remaining deficits after rehabilitation. That’s why many physiotherapists use jump tests to see if the injury is fully gone.

This scientific study used single leg vertical jumps to identify knee problems at return to sport after ACL reconstruction. They conclude that jump height can identify interlimb asymmetries and should be included in the testing battery once previously injured athletes are returning to sport.

How to measure vertical jump

Measuring jump height seems very straightforward at first, but there are some things you need to take into account. Let’s look at the tools/devices you can use and the test protocol.

Vertical jump measurement tool

There are all kinds of high jump measuring devices. The GymAware RS device allows you to dive deep into the data with metrics like:

  • Jump height
  • Dip distance
  • Jump velocity
  • Jump power
  • Mechanical work
GymAware RS hardware features transparent
GymAware RS: vertical jump measurement tool

If you want to detect small changes – good (performance increase) or bad (fatigue) – accuracy of your measurement tool is super important. Contrary to jump mats and force plates, which estimate height based on equations, GymAware measures jump height directly, like a tape measure. As a result, it’s a direct measure opposed to an estimation.

GymAware vertical jump strap attached to the GymAware RS
GymAware measures jump hight directly, like a tape measure. This image shows the simple setup for vertical jump testing, using the GymAware jump strap.

Learn more about the GymAware RS.

Protocol for vertical jump test

A good vertical jump test protocol exists of two things:

  1. The test protocol should reduce sources of variability
  2. The test protocol should be easy to replicate for the athlete

When measuring jump height, you want to be sure that the result is not affected by a variable that you don’t want to measure. 

For example, you might want to limit the effect of arm technique. A good way to reduce this effect is to constrain arm swing by using a broom handle as a barbell. One point to note here though, is that the athlete needs to be instructed (and you need to check for) any tilting of the bar during the jump, as this will produce errors. As an alternative, you could instruct the athlete to put the hands on their hips.

You might also want to standardize the depth of the eccentric dip in a counter movement jump. You could use a box to keep the squat depth consistent.

The second thing you want to make sure is that the athlete replicates the exact same protocol and type of jump during every vertical jump test. So once you have decided on a protocol, you need to make sure your athletes understand it and that they stick to it. Otherwise you will lose the ability to compare results over time.

Let’s continue with the exact steps you need to take to accurately measure jump height, jump velocity and jump power.

GymAware jump test protocol

Here’s how to use the GymAware RS to accurately measure jump metrics.

First decide which jump you’re going to measure: counter movement jump, static squat jump, or any other jump. You should also decide whether you’re going to control squat depth with a box (and if so, which box height).

Then decide whether you’re going to prevent arm swing. If so, decide whether you’ll be using a broom handle (or barbell) or ask the athlete to put the hands on their hips. 

When using a broom handle or barbell, attach the GymAware tether to the handle.

Set up GymAware for measuring jump height
Use a broom handle or barbell, and attach the GymAware tether to it.

Make sure the GymAware RS is placed next to the athlete, clear of their feet. You can place the GymAware RS on the floor or use the brackets to mount it to the ceiling. 

Set up GymAware to the ceiling
GymAware PowerTool mounted to the ceiling, using the brackets. The GymAware PowerTool is now upgraded to GymAware RS.

For more tips and tricks, watch this video:

If you’re not using a broom handle or barbell, you can place the unit between the legs and attach the tether to the GymAware jump strap.

GymAware on the ground to measure jump height
GymAware PowerTool placed between the legs. The GymAware PowerTool is now upgraded to GymAware RS.

Some prefer to put the measurement device into a platform. But this is not necessary.

GymAware PowerTool put into a platform. The GymAware PowerTool is now upgraded to GymAware RS.

For more tips and tricks, watch this video:

Now you’re ready to go! Start measuring via these 3 steps:

  1. Set GymAware to manual record in the GymAware iPad app.
  2. Make sure the athlete stands tall with the feet flat on the floor. 
  3. Press REC/START in the GymAware app. This will set the zero height start position. Anything above this zero point is considered jump height and anything below is considered a dip.

What is a good jump height?

The power of measuring jump height lies in monitoring your own jump height. If you do want to compare your score with normative data, then check out this counter movement jump guideline table:

Male and female normative data vertical jump
Normative data vertical jump

Do this to improve your vertical jump

To jump high, you need to generate a high maximal power output. Power is a combination of force (“strength”) and velocity. So to improve your jump performance, you need to improve force and/or velocity. But which of the two is holding you back?

A force-velocity profile answers this question. It shows the relationship (curve) between your strength (force) and speed (velocity). Use this link to create your own force-velocity profile with the same GymAware device that you used to measure jump height.

Force velocity curve
Force-velocity profile

Once you have your force-velocity profile, you can compare your current force-velocity profile with the optimal force-velocity profile. This comparison tells you what to focus on in training: force or velocity.

Now that you know what you should focus on, you can use velocity training zones to improve your goal. Use high velocity, low load movements to improve velocity. Use low velocity, high load exercises to improve force.

Using velocity (training zones) as a measure to prescribe training is called velocity based training.

Velocity based training zones
Velocity based training: velocity training zoness

This scientific publication – which we recommend reading – shows that the approach of individualized training, based on force-velocity profiling, is much more effective than any generic training program, when trying to improve jump performance.

Additionally, this recently published scientific review (2022) shows that velocity based training improves your vertical jump, with less fatigue. Previous literature already showed that the velocity and power feedback alone (derived from VBT devices) generates greater improvements in jump height.

Learn how velocity based training can help you focus on force or velocity, via this article: Velocity based training training zones explained.

Individualized training, based on force-velocity profiling, is much more effective than any generic training program, when trying to improve jump performance:

Velocity based training improves your vertical jump, with less fatigue.

Velocity and power feedback alone (derived from VBT devices) generates greater improvements in jump height.

Loek Vossen

Loek Vossen

Human Movement Scientist | Content Marketing and Education