Many athletes are never able to jump higher despite training for hours every week.
This is because their training is usually focused on the wrong muscle fiber type.
The 3 main muscle fiber types:
- Type I: Slow Twitch Fibers
- Type IIA: Fast Twitch Fibers
- Type IIB: Fast Twitch Fibers
Type I: Slow Twitch Fibers
Type I muscle fibers are known as slow twitch oxidative muscle fibers.
This is because they contract slowly and sustain these contractions for long periods of time.
Slow twitch fibers are ideal for endurance activities like long distance running.
They contain several mitochondria cells which facilitate oxidative metabolism (the use of oxygen by our bodies).
Slow twitch muscle fibers are therefore resistant to fatigue but produce relatively low force.
They are therefore NOT the muscle fiber that you want to train to jump higher, because slow twitch muscle fibers will not be able to generate a great vertical jump no matter how hard you train them.
What this basically means is that you will not jump higher by running for miles or doing 1000 jump squats, because this only builds your slow twitch fibers.
You will improve your endurance, but your vertical jump will not increase.
Type IIA: Fast Twitch Fibers
These are known as fast twitch oxidative muscle fibers.
They are in the middle of the range of muscle fibers and they fatigue faster, contract faster, and produce more muscular force than slow twitch fibers.
However, they don’t produce as much force as TypeIIB muscle fibers.
They are therefore not as important in vertical jump training.
Type IIB: Fast Twitch Fibers
These are known as fast twitch glycolytic muscle fibers.
Out of the 3 muscle fiber types, they fatigue the fastest and contract the fastest.
They also generate the most force.
They are most used by the body during explosive movements like jumping and sprinting.
They are the fibers that are primarily responsible for vertical jump performance and should therefore be the main focus of your training.
Does Genetics Play A Role?
In general, the more fast twitch fibers you have in your body compared to slow twitch fibers, the more explosive you are and the higher you can jump.
The ratio of your muscle fiber types is a result of what you were born with (genetic).
Genetics therefore plays a role… BUT you can always train your body to make your slow twitch muscle fibers faster.
For example, marathon runners are 75% slow twitch while sprinters are 75% fast twitch (Type IIA &B combined). Both groups of athletes achieve this through training (although genetics does play a part).
Therefore, if you train correctly, you don’t have to have good genetics to be able to jump higher.
How To Train For Fast Twitch Explosiveness
The basic rule for training your fast twitch fibers is to perform exercises explosively.
In the weight room, lift relatively heavy weights, and lift them explosively.
Some great examples of exercises that target your fast twitch fibers are: plyometrics, depth jumps, jump squats, and olympic lifts.
The Jump Manual will show you the all the best exercises to jump higher and become a fast twitch freak.
Finally, you should never overtrain, as this will be training your endurance (slow twitch fibers) and not your explosiveness (fast twitch fibers).