What is a vertical jump?
If you have ended up in this article, I understand that you already know what a vertical jump is, but do you know what the biomechanics of the jumps? The vertical jump consists of a triple flexo-extension, that is, a flexion of the ankle, knee and hip simultaneously,followed by an extension. Although there are different types of jumps and techniques of executing them, in this article we will focus on the counter-movement jump or Counter Movement Jump (CMJ), which is that most closely resembles the jumps made in basketball. The CMJ consists of 3 phases:
- In the descending phase, the hip, knee and ankle joints flex and the muscles of the lower train are stretched, storing elastic force.
- Next, there is an isometric phase in which for an instant the movement stops, it is here where the elastic energy is converted into kinetic force.
- Finally, the quadriceps, hamstrings, buttocks and the likes contract at maximum speed until our feet are detached from the ground.
Biomechanics in jumping plays a fundamental role because depending on your personal characteristics or that of your athletes, the jump itself will be very different.
Through a slow-motion video we can observe the biomechanics of our own vertical jump or that of our athletes and the dominance that this has in the jump itself. If the athlete tilts the trunk forward a lot, we can say that he is mainly dominant of the hip. However, if you don’t bend over much, you may be dominant on your knee to your hip. And on the contrary, nothing may flex at the hip or knee level, so the ankle would become much more important and would be dominant at the ankle level.
We can do different tests to check which are the weakest links and work them to the maximum. For example, if our athlete tilts the trunk a lot and even when we ask him to make a vertical jump from standing, he jumps slightly forward unconsciously, it is that the athlete has a very dominant hip. This will mean that your weak point is the knee extensors and you will need to work with exercises such as squats, partial squat, Bulgarian squat, etc. If, on the other hand, our athlete is dominant of the hip, he should work the opposite part with exercises of hip thrusts bridge of buttocks, deadlift, etc.
It is also very important to keep in mind the concept of SSC or Shortening Stretch Cycle, which we will talk about later.
Improve your power
The power in the jump plays a fundamental role. The power depends on the force that you are able to produce in the shortest possible time, that is, to jump high you not only have to be strong, but you also have to be fast and it is the sum of those two variables that will increase the power and therefore, the height of your vertical jump.
(P = F x V)
Factors influencing vertical jump
- Rate of force development (RFD): It takes approximately 0.4 to 0.7 seconds to reach the maximum force values and in a vertical jump, which occurs in 0.2 seconds, reaching these values is not possible. We can define the term RFD as the slope of the curve between force and time during muscle contraction. This concept has a great importance in the performance in the sports of the team such as basketball. It depends on the efficiency of the central SN which must be able to recruit the maximum number of motor units in the shortest possible time.
To enhance the production of force per unit of time we must keep in mind the different physiological factors that play a very important role.
- Speed of discharge of motor units: The speed of execution of the movement (and ultimately, shortening of the muscle fiber) will modify the contribution of this download speed. The higher download speeds you get at the start of a voluntary maximum shrinkage will allow for a faster response
- Synchronization of motor units: This refers to the timing of discharge of the action potentials and the motor units active simultaneously. The speed of recruitment of motor units, speed of discharge of these motor units, and the synaptic inputs received by motor neurons before starting to generate force, largely dictate the athlete’s ability to generate force quickly.
- Pair of electric shocks: Discharges in the dendrites of spinal motor neurons that cause, thanks to the increase in the release of Ca2+ in the sarcoplasmic reticulum at the beginning of contraction, an increase in the peak of force.
- Recruitment and type of fibers: In our trainings we will look for recruitment type II fibers, which we know as fast-twitch fibers. Its development of strength is 3-5 times greater than the fibers of slow contraction or type I. More specifically, we will seek to recruit the fibers IIb that are the fibers of greater size. These have a high glycolytic capacity and are recruited only when a very fast and very intense effort is required, such as in weightlifting, throwing, or maximum jumps.
- Muscle fiber cross-sectional area: Increasing the cross-sectional area of muscle fiber, and in particular type II fibers, appears to be effective in improving RFD performance.
Finally, within the RFD, there are two main phases. An early phase that covers from the beginning of the contraction to approximately the first 100 ms and depends mainly on neural factors; and a second phase called late phase that occurs approximately towards 200 ms and where structural factors have a greater importance. If we want to improve the early phase, we know that it will be determined by neural factors, which we must address through high execution speeds (and with maximum intention), with the aim of achieving greater recruitment of motor units and this is where the VBT comes into play.
Why train with VBT to improve vertical jumping?
Velocity-based training offers us certain unique benefits in terms of power. If we want to improve our vertical jump, we are looking to improve our neuromuscular strength, that is, to achieve greater contractile enervation. For this, we must keep in mind certain key concepts:
- We must perform the exercises looking for the maximum intentional velocity before any type of load.
- It is recommended to use low loads (40-60% 1RM) or very low (<40% 1RM), away from fatigue, but not necessarily enter only with low loads. It will depend on our goal and priorities.
- Less than 20-30% of the maximum propulsive speed should be lost
If we do not have an encoder like those of Vitruve, during our training we will seek to perform the movement at the maximum possible speed in the concentric phase. When you notice that you lose a significant speed with respect to the first repetition (20-30% of the speed), STOP THE SERIES.
In this way, we will be training with a low stress character, away from failure, avoiding the accumulation of fatigue, both neuromuscular and metabolic caused by the accumulation of lactate and ammonium, which can reduce our performance.
“The greater the fatigue, the less force, and therefore we can generate the speed”
On the other hand, if we already have a Vitruve encoder, with which we can immediately see our % velocity. Our goal will be to beat our own personal best with the load we use regularly.
In addition, you can program the degree of intra-series and inter-series fatigue through the % loss of velocity. In this way, when you perform a repetition with that % loss of velocity with respect to the first series, the encoder will let you know when you need to stop the series.
Velocity tables – % load
The “type” tables, being normative and generic, have a slight problem since we are not all the same and there is, although slight, some variability between people. That is why it is recommended to create your own strength-velocity profile. But how do I do it?
If you have a Vitruve device, it’s actually very simple. During the warm-up, which will be closely related to the exercise or movement we want to measure, you will choose 4 loads, from a low load to a very high load. In this way, the application, through equations, will create your own personal curve and that when you perform ‘X’ exercise you will have your individual and exclusive percentage fully insured. It is interesting that every month and a half approximately we reevalue our speed profile to adapt the loads.
Every day we can work with the loads that we can lift that same day, because we know that every day our athlete or ourselves have a different work capacity. The encoder will give us the exact load to lift at the speeds we want to handle that day.
How to train to improve vertical jumping with VBT?
Strength training becomes key. We must focus our training on those exercises that later have a transfer to the vertical jump on the playing field. These will be those exercises that strengthen the muscles involved in the jump itself, that is, quadriceps, hamstrings, buttocks and the likes.
Exercises such as the squat, deadlift, squat jump or hip thrust can be very good options. We also have to be reminded that the unilaterality of basketball and work from that perspective with exercises such as the Bulgarian squat, the unilateral deadlift or even somewhat more complex movements that resemble the movements we can perform in the game. A clean and press with KB can be a good option.
Plyometric is a training method that involves the stretch-shortening (CEA) cycle. It consists of performing exercises so that the muscles apply maximum strength and power in the shortest possible time. It is a training based especially on jumps and throws, where the muscles in extension exert a fast and explosive contraction. Any exercise in which a quick reaction to impact or rebounds is involved, fall into the category of plyometric exercises.
- Drop Jump: Drop jumps develop the ability to transform the elastic energy stored in the descending phase into kinetic energy during the upward movement of the CEA. The exercise involves jumping from a raised surface and bouncing quickly once the feet touch the ground. Our attentional focus should be directed to the reaction of jumping as soon as we touch the ground.
- Shock jumps: Deep jumps will develop the ability to absorb energy during the downstream phase. It consists of jumping from an elevated surface and landing cushioning the fall. This landing should occur as smoothly as possible, pausing the squat position for a few seconds.
- Multiple Jumps: Multiple jumps will help us improve reactivity and CEA. Unlike the drop jump, in this exercise, we will perform several jumps in a row looking for the maximum possible height. We can put objects between jumps and jumps like half-height fences to force ourselves to jump over and look for a higher takeoff.
When we jump, the stress we exert on our joints and the amount of force they must absorb (reaching up to nine times our own body weight), fatigues the central SN and the joints themselves a lot. It is very important to avoid training plyometric and jumps with fatigue since, apart from reducing our performance and capacity for strength produced, it can increase the risk of injury.
According to scientific evidence, a 10-week training frequently 2 and the performance of between 50-60 jumps will obtain a 9% improvement over our starting point. We can play with the type of jump either with or without the ball, there comes into play the principle of specificity and the role of each player.
- Markovic G. (2007). Does plyometric training improve vertical jump height? A meta-analytical review. British journal of sports medicine, 41(6), 349–355. https://doi.org/10.1136/bjsm.2007.035113
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