ExRx.net

I get all the type IIa's confused all the time, so here is a good article on fiber types and training implications.
http://www.coachr.org/fiber.htm
Tim

Thanks for the article Tim. Damn...its sounds like im definitely slow twitch dominant going by the 80% of 1Rm test. Which really sucks cause it conflicts with my goals of lifting for strength...powerlifting mind, endurance body :(

Well, I believe it actually somewhat depends on the motion.

There is a way to test for it. You calculate your 1RM by actually doing it and then you load up 80% and see how many reps you get. There are ranges that supposedly indicate fiber composition.

Red fiber type can be better for bodybuilding I suppose although bodybuilders can benefit from white fibers that allow them to train heavy and I dont think anyone is PURELY one type. Red fibers are also good for endurance and as a workout lasts longer you can create more red fibers and vice versa. You do have some control over it and do phases to convert to white fibers by emphasizing power exercises and not training to failure. If you are moving the weight slowly then it is being moved by red fibers because the white fibers have a very low capacity for endurance. I should qualify this as slowly for higher reps. because of the nature of 1RM and the like, they do recruit a lot of white fibers and by trying to move the weight as fast as possible, you can recruit more.

Just for your info, there are actually two types of white fibers, type 2a and type 2b.

There is a nice summary here http://www.coachr.org/fiber.htm that I just googled.

And as far as raising your 1RM, dont look at it like you CANT do it. It just means you may get more out of training a certain way. You should just train the way that gives you the best results for your goals.

From what I've read bodybuilders need to develop both red and white muscle fibers. Supposedly, bodybuilders with too high a percentage of white muscle fibers will have mass, but lack definition, while bodybuilders with too much red muscle fiber will have good definition, but lack mass. I don't know how scientific that is.

Ok let me see if im understanding this right. I've been using lower reps almost exclusively for a long time, rarely do i ever do any more than 6 reps in a set. However I do know that on the occasion that i go light on bench press for example i can definitely crank out at least 12 reps at 80% 1RM. Now assuming that my chest is indeed slow twitch dominant, am I right in thinking that if i switched over to higher reps i would see a significant muscle gain in probably a pretty short period of time? Since its like i would be hitting all the previously untapped fibers that im actually dominant in??

Also it sounds like from the article that some of your muscles can be slow, and others can be fast twitch(along with being a possible mix of course). Is this correct as well? Like its possible my chest could be slow twitch but my quads fast twitch dominant?? This is peaking my curiosity now!

Yes I believe you are correct jeff on both your statements about training higher reps for a bit being beneficial and about differing composition locally.

So what you've been doing is building strength, changing your regimine would likely build muscle mass without building strength, though it may add to your 'base' of strength, what might be described as muscle endurance. Lifting in a different way (to build slow twitch) will give you gains in slow twitch strength. This probably won't help when you go back to fast twitch lifting... except maybe when you hit a sticking point and need to power it out.

So going slow with reps and doing 8-10 per set could be a good change for a three month stint.

So for a powerlifter or thrower in track and field, you are fighting red fibers BUT at some point you have probably converted as much as you can, so if you want to get stronger, you can add a little mass and you can do that by training the red fibers and then converting them.

I do not know the details of how this works but I am pretty sure this is the idea, especially for sports.

You also want to detrain at some points throughout the year, in the sense that you should go back to basics, make sure your basic athletic skills are good, balance, ROM, address weaknesses perhaps, and give your body a break from taxing lifting. This can refresh the body for the next cycle and then you can either begin a max strength or hyptrophy cycle. If you want to get more powerful you then train power conversion.

Tudor Bompa has a really good book for sports training and I think he has one for bodybuilding as well. You should also read about supercompensation probably just a google search would help, but this just says you need to be in a state of "overreaching" and then reduce volume/frequency and allow your body to supercomensate and increase performance.

Another method to develop both slow and fast twitch fibers is to varry reps from week to week. You can alternate light and heavy weeks, try a powerlifting style periodization program like the ones on this site.

Ryan, those books are "Serious Strength Training" which is geared to bodybuilding and general fitness, and deals with fiber types, etc, and most of all lists different phases of periodization, and setups. "Periodization Training For Sports" deals with all the above, but is geared to athletes. What is interesting, is that the MxS (maximal Strength) and H (hypertrophy) phases are somewhat different between the books.
Tim

Yeah Tim,

I actually just made it all the way through Training for Sports and found it very informative as a back to basics type approach, especially after all the westside stuff I have been used to the past couple years.

Since my goals are mostly for sports now, I have given up on lifting superheavy in the big 3 for any reason other than to increase performance in sports. I noticed I never went though a power phase as outlined by Bompa and I think this is probably why I have been making lackluster progress and it is funny because he sites this as a big problem (funny how I fell right into it).

I mentioned the other one because matt seems more into bodybuilding.

Care to mention the main differences between the mxS and H phases between the two? I am familiar with the sports ones but interested to hear how they differ.

Hi Ryan. LOL, ust off the top, in the MXS phase Bompa recommends circuits with lots of rest in between exercises, not so i the BB oriented one. Anyway, gotta break bgoth out of the attic, and will give details in a separate thread marked "for Ryan-Bompa". Probably later on today. It's nice and stormy here, so I can get to it quickly.
Tim

Well I think the article said that you can't convert one muscle fiber type to another, i.e. what you're born with is what you have. But there they're talking about the composition of fibers, 50-50 in terms of numbers, not strength or size. What you can do is train both types of fibers so that each increases in volume. Basically the periodization/'changing it up' thing that most lifters do anyway is supported by this article. Alternating training fast-twitch and slow-twitch fibers is probably the best way to increase overall size.

Well, while it's true you won't convert type I's to II's (slow vs fast), there currently are questions of conversions of IIa's to IIB's and vice versa. Is it how you train, or what you were born with that determines these characteristics between the ype II's. Last I heard the jury was still out.
Tim

Oh I see, my bad. Well they do mostly the same work anyway right? So maybe train specifically for each type...?