Thread: Changing muscle fibers to fast twitch

Hello,

Currently, I am training at the gym 3-4 times a week. My training consists of approx 4-5 exercises (3 sets for each with the rep range of 6-8). I am researching into muscle fibers to assist me with sprinting. A trainer at my gym believes that training in the 1-4 rep range will change my 50/50 balance to a balance that favours my fast twitch fibers. I can understand that using high weights and lower reps will give me higher strength and more explosive speed whilst sprinting but will it give me more fast twitch fibers?

Will training 1-4 reps increase my strength?
Will it increase my size? (I am not looking to gain size)
Will training in this rep range increase my overall speed?

Thanx

Originally Posted by P-funk

fiber types don't change between type I and type II. There is a change between characteristics however from type II to to type I (but not the other way around). So, if you have a high amount of type II fibers genetically and all you do is cardio, while you can't change the fiber type and its qualities, you can make it more oxadative in nature (but it still wont have the qualities of a type I muscle fiber....ie, higher capillary density, etc..). The only actual changing of fiber types that I have seen documented was from type IIb to type IIa (again, not a two way street. they only change one way). So if you have a high amount of type IIb and you train more aerobically or lift weights with more moderate intensiteis, you will alter the make up of those fibers to be more type IIa (more oxidative, less power oriented).

to, to answer your questions:

1) yes, a 1-4 rep range will increase your strength.
2) it may or may not increase your size. for size gains a higher amount of reps (8-12) with a greater TUT will be more beneficial. However, if you lift in a strength rep range and eat enough food you will gain size.
3) training in that rep range will increase your strength and may help to improve your speed but you will also need to train in a rep range that can help to improve your power (ie, mod. intensity loads for low reps and the highest velocity. like, 75-85% of 1RM for 3-5sets of 5 reps as fast as you can move. or 80-90% of 1RM for 3-5 sets for 1-2 reps as fast as you can move). This will train your CSN to recruit maximum number of fibers in the quickest, most effecient, way possible.

nuff said