Definition of Flexibility
For our purposes, flexibility is defined as the amount of range of motion around a joint. The more motion that you have in a joint, the more flexible that you are.
Importance of Flexibility
Some research has shown that lack of flexibility has a more negative impact on sports performance than any other factor. That means that no matter how much you lift, run, or jump, if you aren’t flexible, you will not likely perform well in your sport.
This is because there is a length-tension relationship that we must take advantage of for running fast or jumping high. That means that in order to get the full potential strength and power out of a muscle, we need to be able to use as much of the length of the muscle as possible. Once the muscle is pre-stretched, it is ready for quick and explosive action. If you are too tight, you may not be able to put certain muscles on a pre-stretch, thus robbing you of power.
Another way that lack of flexibility will affect your performance is through joint and body positioning. If you are tight in specific muscle groups, you may not be able to put parts of your body in positions that are advantageous for your performance. For example, if you are tight in your calf muscles, you likely will walk with your feet pointed outward. Running and jumping with your feet pointed outward in this way will cause you to only use half of your calf muscle when it contracts. It’s not hard to figure out that this will limit your performance.
Likewise if you are trying to sprint with tight hip flexors, you will not be able to reach full hip extension when you are pushing against the ground to sprint. This will limit your glute and hip firing, which will rob you of valuable power.