T Nation

Muscle Fibre ?'s


I am abit confused - Reading up on muscle fibre types I assume that if you have a higher proportion of typeII (FAST twitch) muscle fibres you would be stronger AND faster.

I notice a strange disparity with me.

In self-tests for muscle fibre distribution (vertical jump test and 80% of 1RM) it seems to indicate that I have a very high proportion of fast twitch fibers. And although Im not huge I tend to be (alot) stronger than most of my friends, I also tend to gain strength alot quicker than my friends. This is fine and all.

What I can't understand is, I am much SLOWER (not as explosive) than them, while being leaner and lighter. If we play games which require hand speed, like trying to snatch something from the others fist before closing it I lag behind.

If I have higher fast twitch muscle fibers than they, shouldnt I be faster too? What am I missing? Is it a matter of practise then?

I found something interesting when we practise sprinting aswell, I take longer to accelerate to top speed but once I reach my top speed I am faster than my friends. Over 100m-400m I beat them quite comfortably, I cannot do long distance though.

This is not the most serious issue in the world but a point of curiosity with me and would be interested in input.

Thank You!


Perhaps this is because success at playing games like the above is also a function of nervous system efficiency which probably isnt directly related to proportion of fiber types. In other words having fast twitch fibers doesn't necessarily give you fast reflexes (which involve the eyes the brain and the nerves as well as the muscles).


Good Point!


I remember reading something from Charles Poliquin about the effects of a certain mineral (I think it was mercury?) and how it inhibits muscular endurance to the point where using a test like the 80% of 1RM were less accurate because of the mineral.

He said that most of the people who thought of themselves as fast twitch dominant, who then lessened their intake of the mineral, noticed that their ability to get more reps with their 80% of 1RM increased, thus showing a more slow-twitch dominance.

Sorry about not knowing all the facts, I know I'm not doing Charles justice here, and I'm not saying that you aren't realy fast-twitch dominant, just that there may be a mineral surplus affecting your muscular endurance and the testing.

Maybe someone else knows what I'm talking about more than I do, LOL.


I have considered that...but on my vertical jump test there is a 59cm difference between where first mark and when I jump-mark, and even though Im smaller, Im still considerably stronger in most of my lifts.

My "explosiveness" seems to lag behind though and it just perplexed me why I could be stronger, yet slower, while being lighter.

Perhaps I should be practising more explosive techniques instead of simply lifting heavy weight.


I think it might have something to do with explosive strength (lifting fast like a Dynamic Effort day in Westside type of training) as opposed to just raw strength.

There's a difference there, and I think I remember Chad Waterbury mentioning that's why you should always try to lift fast, even if it's a weight that is heavy and the load moves slow. He has said something about moving the weight slowly will train the muscles to move slowly.

I'm thinking that this has nothing to do with the muscle type, which would explain your situation. I don't know if it's purely a CNS thing or not.

Again, sorry about not knowing the details.


You have to specifically train to have a greater rate of force development, regardless of fiber typing. Try incorporating snatches, cleans, and depth jumps pretty extensively for a while and see how well you do.



That's very interesting. So, what foods are high in mercury besides tuna? Didn't he also recommend taking a supplement to minimize mercury effect? Maybe Niacin?


I never really ate tuna (was paranoid) until recently I read the article on T-Nation that having some tuna wasnt so bad for you afterall. Im still abit suspect but I've included it more. It seems like the ideal food if only it was not poisened.

Is there any merit in training your ordinary main lifts using lighter weight but executing them as fast as possible? What % of your 1RM is best for this type of work offhand? Does speed training contribute to actual hypertrophy aswell?

The majority of my training has been using big lifts (Squat/Row/Dip) as controlled as possible to avoid momentum.