FAST TWITCH VS SLOW TWITCH FIBERS
When I talk to clients about training in the gym, the main focus is about fast twitch muscle fibers, and for good reason! They have more mass, create more force, bring in more blood volume and personally I think are more fun to train. However, I've been experimenting with their partner, the slow twitch fibers.
There are two primary reasons that I have incorporated some slow twitch training in my program and with my clients. First is that they are still muscle fibers and therefore, by giving them some love, overall they should contribute to muscle development. Secondly, slow twitch fibers recover faster so you can add more training in and not lengthen out recovery time.
The key on slow twitch fibers is higher reps. I like to do the 15 to 30 range. Obviously the exercises are chosen accordingly so the cardiovascular system doesn't get overly taxed. It's important when doing these higher rep sets that the mind/muscle connection stays in place and feeling each rep. I know it is easy to try to crank the reps out with lighter weights so keep the focus on.
The burn is different too. With fast twitch training, muscle failure comes quick and obvious, whereas the slow twitch is a different type of fatigue to push through.
Next time you see some high reps sets in a program, know what the purpose is and that it's not a typo.