Fast Twitch - Slow Twitch
Run 1 Mile For Time
During aerobic exercises such as running or swimming, slow-twitch fibers are the first to contract. When the slow-twitch fibers become tired, fast-twitch fibers begin to take over.
There are significant benefits to working to the point of temporary fatigue—and therefore making sure fast-twitch fibers have been recruited. For instance, if you're looking to increase muscle mass, and improve strength, using fast-twitch fibers is the only way to do it. On the other hand, aerobic exercises, those that mainly use slow-twitch fibers, can increase stamina and the oxygen capacity of your muscles, allowing the body to burn energy for longer periods of time. A high proportion of slow-twitch fibers has also been associated with low blood pressure. (Greatist.com)
When muscles are forced to work differently and you get out of your comfort zone, you get a better workout response. This is the constant goal of CrossFit training. Keep mixing your workouts up to recruit all types of muscles fibers. Be able to lift heavy, run fast, jump high, swim long - variance is key!