The vertical jump test is one of the most widely used physical tests to measure lower body power. In 1921, Dudley Allen Sargent was the first to start using and researching the vertical jump to measure athletic capability (1). The test has evolved over the last 100 years to become one of the most widely used tests by all levels of practitioners and coaches. Vertical jump tests are also used in research and applied settings for a wide variety of reasons around athletic development and performance, such as monitoring if an athlete is adapting to a training program (2). One of the main reasons this test is used in athletic development is because of its relative ease to conduct and perform. There are a wide variety of vertical jump tests that have been validated, and with technological advancements, there are several types of vertical jump testing tools that are available for all levels of coaches.

Selecting what type of vertical jump test to use with athletes is determined by the coach. The countermovement jump (CMJ) is one of the most widely used tests to assess lower body power. The movement needed to perform the CMJ involves rapidly dropping the centre of mass, followed by rapidly decelerating and then propelling oneself off the ground. Since the movement involves a drop in mass follow by concentrically contracting upwards, it requires the use of the neuromuscular system to perform the movement. The involvement of the neuromuscular system in the CMJ can allow us to use the results as a predictor of neuromuscular involvement (2).

Since the CMJ has the versatility to assess fatigue and performance, coaches can use CMJ metrics to assess both negative and positive adaption to various stressors of training. This can be accomplished through regular testing of the athlete’s CMJ. Typically, coaches might test athlete’s CMJ weekly, biweekly, or monthly. In order to create a profile that provides information on adaptation, the testing needs to be done regularly. Daily testing is ideal, but not everyone has access to their athletes every day. If you see your athletes 3 times a week, then test them 3 days a week as it will still give you some variation you can use.

Figure 1 is an example of daily CMJ testing during a 3-week competition phase. The metric used was jump height in centimeters, and the data was collected by the Exsurgo Technologies GFlight. The athlete did three jumps, and the best score of the three was used for the variation profile. In order to track the variation properly, you need to create a CMJ fingerprint. That is done by calculating the mean and the standard deviation from the daily jump height data.  The standard deviation can be used to create a range around the mean that will provide information about the variation that is happening on a daily basis. Inside the standard deviation lines would be considered the “fingerprint” for the individual athlete. Any variation inside that fingerprint would be considered minor changes based on the athlete’s day to day. When we see anything outside of the fingerprint, we know there are some major changes happening. For example, on day 12 there was a major dip that occurred well below the lower level of the standard deviation. This would be considered negative variation. So, by using this data you have the ability to explore what happened to create such a drastic change.  When reviewing this particular athlete’s wellness questionnaire, it was noted they had a slight neck injury on day 11. That neck injury affected their sleep increasing fatigue levels. Having this information allowed the coach to alter the training plan to maximize recovery. In this case, the coach’s option was to carry forward with the original training plan, reduce the volume of the training, or give the athlete the day off to recovery. After a discussion with the athlete, the coach decided to give the athlete the day off from training to rest.

It may sound challenging to run daily CMJ tests for your athletes, but when we use a simple metric like jump height in centimeters, almost any coach from all levels could use this evaluation to assess athlete progress. There are various equipment options for coaches to choose from that will provide them with jump height. The following is a list of equipment that can be used to assess vertical jump, they are listed based on reliability as Gold – Silver – Bronze.

Gold – Force plates. These provide a wide variety of data regarding jumping ability, including jump height. The top-rated force plates will provide the user with accuracy and reliability if procedures are followed consistently.

Silver – Velocity based tools, and the Exsurgo Technologies GFlight. These tools have been validated in various studies, and if used correctly can provide reliability in your data (4, 5).

Bronze – “My Jump 2” app and jump and reach systems such as the Vertec or a wall with chalk markings. The My Jump 2 app has been validated as a reliable source for jump height but can be time consuming (6). Based on experience, the jump and reach system would be the accessible way to measure vertical jump for most coaches. Typically, the CMJ test is done with the athlete placing their hands on their hip during the jump. This method focuses measurement on lower body power. The jump and reach method would involve the upper body as well, making it a measure of jumping ability. This changes the tests focus, as it would be skill and lower body power.

The systems listed in gold and silver are quite costly and will be outside of most coaches’ budget. However, when it comes to assessing fatigue in CMJ, jump height alone is not sensitive to fatigue. Peak force and power metrics along with jump height will provide a better assessment of fatigue. Therefore, force plates are ideal for measuring fatigue (2). The bronze list would be the most affordable form of jump testing. The My Jump 2 app is $17.99, while the jump and reach method only requires a wall, some chalk, and a tape measure.  The jump and reach method only gives you jump height, so the accuracy would not be at the same level as the force plate. But involving the standard deviation in your data will help limit some of the typical error when only using jump height.

The key to developing a successful variation profile is making sure that you follow the same procedures when conducting your CMJ assessments. This way the data collected will be reliable enough to provide you with information that can help your athletes do quality work each day. Also, this is a way for any coach to incorporate some sports science into their program. We also need to understand that CMJ alone won’t indicate fatigue, involving wellness questionnaires, heart rate measures, and just communicating with the athlete will paint a far bigger picture. This also might seem like something you would see in the professional or collegiate ranks, but with the right equipment, a good spreadsheet, and some consistency, any level of coach could use this tool. Whether you are a parent coach, high school coach, or working with elite athletes, utilizing the CMJs ability to tap into the central nervous system is a great way to help your athletes perform better during the season.

Brent is a faculty member in the Department of Kinesiology at Langara College. His role at Langara College includes teaching various Kinesiology courses and being part of the Applied Human Performance Research Team. Brent is also the founder of Real Kinetic Fitness, where he consults with various athletes and coaches on strength and conditioning programing.

References:

1. Price, A. (2016). Year of the dunk: a modest defiance of gravity. Sports Pub. P.165.
2. Wu, P. P.-Y., Sterkenburg, N., Everett, K., Chapman, D. W., White, N., & Mengersen, K. (2019). Predicting fatigue using countermovement jump force-time signatures: PCA can distinguish neuromuscular versus metabolic fatigue. PLOS ONE, 14(7). https://doi.org/10.1371/journal.pone.0219295 
3. Roethlingshoefer, J., & McConnell, D. (2018). Intent: a practical approach to applied sport science for athletic development. Freeze Time Media. 
4. Wadhi, T., Rauch, J., Tamulevicius, N., Andersen, J., & De Souza, E. (2018). Validity and Reliability of the GymAware Linear Position Transducer for Squat Jump and Counter-Movement Jump Height. Sports, 6(4), 177. https://doi.org/10.3390/sports6040177 
5. Parmar, A., Keenan, A., & Barry, G. (2021). Concurrent validity of the portable gFlight system compared to a force plate to measure jump performance variables. Physiological Measurement, 42(1), 015003. https://doi.org/10.1088/1361-6579/abd236 
6. Bogataj, Š., Pajek, M., Hadžić, V., Andrašić, S., Padulo, J., & Trajković, N. (2020). Validity, Reliability, and usefulness of My Jump 2 App for measuring vertical jump in primary school children. International Journal of Environmental Research and Public Health, 17(10), 3708. https://doi.org/10.3390/ijerph17103708