Know your muscle fibers

The Three Main Muscle Fiber Types

Although there are further micro variations in muscle fiber types, the three main ones are:
Type I: Slow Twitch Fibers.
Type IIa: Fast Twitch Fibers.
Type IIb: Fast Twitch Fibers

Each one has its own characteristics and is suited to a particular type of movement.

Type 1 fibers are slow to contract (hence, slow twitch), and can sustain muscular contractions for an extended period of time. This makes them ideal for endurance type of events where one is exercising for a longer duration. They also contain large and numerous mitochondria which aid in their oxidative metabolism (the use of oxygen). These types of fibers are fatigue resistant but are only able to produce a relatively low level of force output.

Type IIa muscle fibers are, as the name would suggest, fast twitch fibers (FTF's). However they are in the middle of the muscle fiber spectrum, as they are less fatigue resistance, produce more muscular force, and contract at a faster speed than slow twitch fibers, but not quite as much as type IIb fibers.

The type IIb fibers are the most easily fatigued out of all the fibers but also generate the most power. These are most heavily recruited for activities that require an all out burst of power over a very short period of time.

How To Train Fast Twitch Muscle Fibers

There are a number of proven methods that target the fast twitch muscle fibers FTF. By following these guidelines you will ensure that your muscles are provided with the right type of training stimulus for developing your vertical jump.

• In the weight room try to lift in excess of 60% of your 1RM.
Generally speaking, the heavier you lift the greater the recruitment of FTF's. The exception to this is if you are doing ballistic weighted exercises such as barbell jump squats. In these instances it is ok to use a lower % of your 1RM - see the next point.


• Aim for maximum speed on all your movements.
Whether it is lifting a weight, skipping, jumping, bounding, or throwing, try and do it flat out. Short burst (10 seconds or less) of very high intensity work will cause the type of positive muscular adaptations you are after.


• Train eccentrically.
Eccentric training refers to emphasizing the work done as you lower a weight or descend in a jump. For weighted work this would be done using bands to accelerate gravity, or using drop and catch motions such as reactive squats. For jumping exercises the eccentric portion is emphasized in movements such as the various types of depth jump and altitude landings (see next point).


• Plyometrics.
Plyometrics involves the activation of the stretch-shorten reflexive response to create more powerful contractions. These contractions are primarily the domain of the fast twitch muscle fibers so doing this type of training will really stimulate those type II's.


• Contrast Load Training.
This is one of our favorite training techniques and real jump improver. To use contrast load training you might perform a very heavy set of squats, say 75-95% of your 1RM, rest 1-2 minutes, and then perform a lighter more explosive movement such as unweighted jump squats. The initial heavy set fires up a process known as potentiation that triggers higher recruitment of fast twitch fibers in the subsequent exercise.


• Over-speed Training.
Overspeed training is where you add some form of assistance such as having a partner pull you along, using bands to pull you along, or simply running down a slight hill. This trains your body to move faster than it otherwise would have by forcibly recruiting the FTF's for the extra speed, and it reinforces to your brain how to send those messages that fire up the FTF's.


• Mental Training.
If you have ever seen an Olympic lifter before a lift you will know what a psyche up is. This is part of mental training. Those lifters are essentially getting into a frame of mind that tells their bodies to literally fire up the fast twitch fibers. It works equally in your jumping and training. Spend 20 seconds before a jump mentally preparing for the effort and you will jump higher than if you just go and do it. Why does this work? Because the psyche up is a method of getting your brain ready to send the signals to the fast twitch muscles that they are about to do some maximum effort work.