Jump Height and Absolute Strength: An Indirect Relationship

 

One of the most commonly talked about topics in strength and conditioning is the role that maximal strength plays in performance and whether or not it is necessary.

Before I dive into this topic, let me get some of the confusion out of the way. Maximal strength is not only important for performance, but it is mandatory. Without some level of maximal strength, there is no way any effort of great power could ever be performed.

How Does Maximal Strength Influence Movement?

Throughout this article, I am going to use the vertical jumping movement to help explain how maximal strength plays a prominent role in athletic development.

Looking at the above picture, we can see that “jump height” is our primary goal of training and as we know, thanks to physics, takeoff velocity is what determines how high someone will jump. Thus, one can quickly see that “velocity” is the most important factor regarding jump height. This is true, but the process in which velocity is produced is a little more complex than simply saying “velocity dictates jump height”.

How Is Velocity Developed?

Takeoff velocity is developed via the movement’s impulse. Thus, the takeoff velocity is dictated by the total accumulated impulse one can develop during the vertical jump.

Impulse: Force x Time = Change in momentum

 

As we see from the impulse equation, force and time are of great importance in producing maximal takeoff velocity. In sport, we don’t always have the luxury to increase our time of movement (we want to move fast), so naturally, force is the only variable we can really change.

Because force and the time in which the force is produced is of importance, one can quickly see that the “magnitude of absolute strength” that can be produced within this specific time frame is critical. However, it takes time to produce a given percentage of absolute strength. For example, it may take longer for an athlete to generate 80% of absolute strength than it does for this athlete to generate 60% of absolute strength….

Finally, we get to the importance of absolute strength. The stronger someone is, the greater 60% of absolute strength will be. For example, if two athletes can only produce 60% of absolute strength in the time framed allowed to perform a movement, the person with a larger absolute strength will obviously produce more force (same percentage, but a bigger piece because the pie is larger).

External Load

External load also needs to be considered. The magnitude of the external load will also dictate the necessary magnitude of absolute strength that will need to be produced. If you look at the above picture, you will see this connection is made with a hashed line. The hashed line signifies the fact that external load is highly variable and depends on the specific event. In other words, the heavier the external object, such as someone’s body weight, the more maximal strength they will ultimately need.

Conclusion

In depth analysis allows for critical details regarding sporting development to be sifted through. Only once such analysis has been done, specific qualities can be separated. By using simple field tests, a coach can tests these qualities to see how they are facilitating the development of a given sporting movement.

 

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