Used most often by basketball players and football players, the vertical jump is a complex and multifaceted movement. It is both highly technical and utterly basic.
Children naturally learn how to jump by testing a wobbly hop, learning how to balance a landing and take-off, and everything in between. Some seem to be naturally better jumpers than others.
This is clearly demonstrated in children who have never had jump training, and who are the same body shape and size, yet one jumps significantly higher than the other.
In these cases, one wonders what makes a good jumper, and if it can be changed with training.
In truth, the height reached in a vertical jump is both a result of natural and developed skills and muscle physiology.
How Does A Muscle Contract?
Muscles are told to contract by nerve messages. These messages are generated in the brain’s motor cortex. This part of the brain is where the idea to leap into the air is born.
The brain sends a message, calculating simultaneously the trajectory and forces needed for the desired movement.
In a few 100ths of a second, the messages are transmitted down to the muscles and a simple muscle sections contract.
In a jump movement, the brain is sending messages through hundreds of nerves to dozens of muscles throughout the body.
In this way, while a muscle contraction is simple ‘wiggle your toes’ it is the speed of message transmission and the sequence, or order of muscle contractions, along with overall force generated which leads to a successful jump.
A perfect example of how the muscles work together would be to try standing up and jumping as high as possible without bending the knees, or without bending the hips.
The cooperation of the whole body is necessary for success.
Force Of Contraction
In the moment when nerve cells initiate muscle contraction, another factor is at play for not only a successful jump but the height reached in as a result of the force of muscle contraction.
The force generated in a movement varies greatly from one person to another.
This is one of the variable factors in jump height.
This is also a trainable factor, which can adapt to eliciting more and more force per contraction.
How To Improve Contraction Force
If you’ve been adding weight to the leg press, and increasing the strength of the legs, you may have only noticed a slight difference in vertical height.
This is because contraction force is not only represented in muscle strength, but also in power. While often confused for being the same thing, muscle strength and muscle power are two different measures.
In the moment of contraction, the speed at which maximal strength is applied is known as power.
The overal power generated cannot be improved by only training the strength component. Improving the speed of contraction is required as well.
In training, this means focusing on specific exercises that improve overall power generated by the legs.
It means doing movements which incorporate power training as much as possible.
This also means that the specific muscle fiber types which are used in extreme force and power generation will be trained, and adapted, and possibly increase in numbers.
Fast And Slow Twitch Muscle Fibers
There are two basic types of muscle fibers; type 1 and type 2.
Type 1 is known as slow twitch – these are endurant, slower responding, long lasting muscle fibers which are highly developed in endurance athletes.
Type 2 is also known as fast twitch and they are broken down into Type 2a and 2b.
These muscle fibers are able to generate incredible amounts of force, are responsible for explosive movements, but are very short-lived.
They are highly developed in sprinters and power-based athletes.
Most physiologists agree that these fiber types are present in different ratios in every person.
This explains why one person may be stronger in either category, regardless of conditioning, while another is weak in it.
Many physiologists also argue that these fiber types are adaptable to conditions and demands placed on them.
This is to say that even if a person may be born with a natural split between the two that they can train type 1 fibers to become type 2a or type 2b fiber types.
Type 2b is the most explosive, most powerful and quickest muscle fibers to contract.
These contractions last up to 5 or 6 seconds at the most, and are most likely those recruited in a vertical jump.
With this in mind, type 2a can be trained with time to be as strong and responsive as 2b.
But this is often where the challenge lies. While it may be physiologically possible, many lack the training expertise to create an appropriate goal oriented program.
While some may be naturally inclined towards endurance athletics, others may be at the other extreme, towards power athletics, with the rest in between.
A solid training program like the one provided in The Jump Manual, and dedication to it can lead to serious physiological adaptations to vertical jump training.