T Nation

Slow Twitch to Fast Twitch?

Im a sprinter and some might know that sprinting requires quite a bit of fast twitch fibers.

How can I help transform the slow twitch to fast twitch? I know that you cant change them persay, but I read that you can make them act like fast twitch fibers.

So, are there any workouts that can help to transform slow twitch fibers to fast twitch?

Thanks

Forgot to mention that im a college freshman

You cant do that man.
Everybody is born with a certain ratio of fast twitch to slow twitch, you can only make the ones you already got stronger.

You cannot change a slow-oxidative fiber to a fast-glycolytic fiber, just not going to happen. What you can do through training is maximize your ability to recruit the fibers that you do have, as well as increase the ability of each fiber to operate at or near its full potential.

The way to do this is to simply train for your event. If you are doing proper sprint training (and there are plenty of resources both here at T-Nation and elsewhere that describe proper training programs) then you will by virtue of doing so maximize your fiber recruitment.

So basically don?t stress about your fiber makeup, just train your event and you will improve.

[quote]DanErickson wrote:
You cant do that man.
Everybody is born with a certain ratio of fast twitch to slow twitch, you can only make the ones you already got stronger.[/quote]

Please don’t listen to this. This statement is so wrong it makes my brain itself hurt to read it.

You indeed can change slow twitch to fast twitch fibers through high force, eccentric based training, such as depth jumps/drops, drop and catch weight movements, and sprints.

However, training with excessive volume will eliminate these effects, and will likely lower fast twitch count.

I think you are really just asking how to get faster. I will assume you are in high school. Probably the best way for someone at your level to get faster is just get stronger. Focus on your glutes/hamstrings in your weight room, doing mainly hip extension work.

Combined with your normal sprint training, your times will keep dropping, as long as you aren’t overexerting yourself. For sprinters, less work at a higher intensity will give better results than a lot of volume.

[quote]RJ24 wrote:
DanErickson wrote:
You cant do that man.
Everybody is born with a certain ratio of fast twitch to slow twitch, you can only make the ones you already got stronger.

Please don’t listen to this. This statement is so wrong it makes my brain itself hurt to read it.

You indeed can change slow twitch to fast twitch fibers through high force, eccentric based training, such as depth jumps/drops, drop and catch weight movements, and sprints.

However, training with excessive volume will eliminate these effects, and will likely lower fast twitch count.

[/quote]

No you cant.

[quote]RJ24 wrote:
Please don’t listen to this. This statement is so wrong it makes my brain itself hurt to read it.

You indeed can change slow twitch to fast twitch fibers through high force, eccentric based training, such as depth jumps/drops, drop and catch weight movements, and sprints.
[/quote]

You, my friend, have no clue about what you are talking about. I’m sure your brain hurts, but it’s probably from the effort of tying your own shoes.

Good luck, Forrest.

To the OP, do like the others are suggesting - train with power moves and your sprint workouts and you should be fine. You won’t change slow to fast but you will maximize the potential of your existing FT fibers through hypertrophy, intramuscular coordination adn intermuscular coordination. Good luck

cb.

[quote]smallmike wrote:
I will assume you are in high school [/quote]

Thus showing you didn’t read his post.

The OP has it right; you can’t strictly change ST to FT fibers through natural means, but you sure as hell can shift their characteristics more towards fast twitch.

To the OP, though, this won’t really affect your training. ST fibers will morph slightly towards FT characteristics the same way you get your FT fibers stronger and more explosive, so it really just kind of happens as you train correctly for your sport.

Believe me, I wish there was another way too, I’m a slow-twitch dominant mofo.

-Dan

[quote]DanErickson wrote:
You cant do that man.
Everybody is born with a certain ratio of fast twitch to slow twitch, you can only make the ones you already got stronger.[/quote]

They can change. Parapalegics have been found to have 70% fast twitch. Training will either cause genetic expression switch to IIa or I. I believe its been shown that detraining causes a reversion to IIx (or IIb) but all methods of training reduce type IIx fibers.

If you’ve heard or read differently I’m interested.

[quote]buffalokilla wrote:
smallmike wrote:
I will assume you are in high school

Thus showing you didn’t read his post.
[/quote]

Actually, I think he added it in later. But I should have looked at his profile anyway to see if it was there.

[quote]Cam Birtwell wrote:
RJ24 wrote:
Please don’t listen to this. This statement is so wrong it makes my brain itself hurt to read it.

You indeed can change slow twitch to fast twitch fibers through high force, eccentric based training, such as depth jumps/drops, drop and catch weight movements, and sprints.

You, my friend, have no clue about what you are talking about. I’m sure your brain hurts, but it’s probably from the effort of tying your own shoes.

Good luck, Forrest.

To the OP, do like the others are suggesting - train with power moves and your sprint workouts and you should be fine. You won’t change slow to fast but you will maximize the potential of your existing FT fibers through hypertrophy, intramuscular coordination adn intermuscular coordination. Good luck

cb.[/quote]

No need to be rude. I’m about to prove you wrong.

Adaptation to chronic eccentric exercise in humans: the influence of contraction velocity.

    * Paddon-Jones D,
    * Leveritt M,
    * Lonergan A,
    * Abernethy P.

Department of Surgery, University of Texas Medical Branch, Galveston 77550, USA. djpaddon@utmb.edu

We compared changes in muscle fibre composition and muscle strength indices following a 10 week isokinetic resistance training programme consisting of fast (3.14 rad x s(-1)) or slow (0.52 rad x s(-1)) velocity eccentric muscle contractions. A group of 20 non-resistance trained subjects were assigned to a FAST (n = 7), SLOW (n = 6) or non-training CONTROL (n = 7) group. A unilateral training protocol targeted the elbow flexor muscle group and consisted of 24 maximal eccentric isokinetic contractions (four sets of six repetitions) performed three times a week for 10 weeks. Muscle biopsy samples were obtained from the belly of the biceps brachii. Isometric torque and concentric and eccentric torque at 0.52 and 3.14 rad x s(-1) were examined at 0, 5 and 10 weeks. After 10 weeks, the FAST group demonstrated significant [mean (SEM)] increases in eccentric [29.6 (6.4)%] and concentric torque [27.4 (7.3)%] at 3.14 rad x s(-1), isometric torque [21.3 (4.3)%] and eccentric torque [25.2 (7.2)%] at 0.52 rad x s(-1). The percentage of type I fibres in the FAST group decreased from [53.8 (6.6)% to 39.1 (4.4)%] while type IIb fibre percentage increased from [5.8 (1.9)% to 12.9 (3.3)%; P < 0.05]. In contrast, the SLOW group did not experience significant changes in muscle fibre type or muscle torque. We conclude that neuromuscular adaptations to eccentric training stimuli may be influenced by differences in the ability to cope with chronic exposure to relatively fast and slow eccentric contraction velocities. Possible mechanisms include greater cumulative damage to contractile tissues or stress induced by slow eccentric muscle contractions.

As you can see, it is indeed possible to change your fiber type ratio. Now, try and think before insulting someone.

Well… I read that you are born with a certain ratio of fast twitch to slow twitch.
Read it in one of the mens health books

Either Testosterone Advantage Plan, or Hard Body Plan

[quote]DanErickson wrote:
Well… I read that you are born with a certain ratio of fast twitch to slow twitch.
Read it in one of the mens health books

Either Testosterone Advantage Plan, or Hard Body Plan[/quote]

Well, I’m sorry to tell you that not only is that information from a poor source, but it’s also probably outdated. No hard feelings though, I’m just trying to stop the flow of misinformation.

For those who are interested, here’s yet another study:

Changes in muscle strength, muscle fibre size and myofibrillar gene expression after immobilization and retraining in humans
T. Hortob?gyi, L. Dempsey, D. Fraser, D. Zheng *, G. Hamilton?, J. Lambert and L. Dohm *
Biomechanics Laboratory and Departments of * Biochemistry and ? Physical Therapy, East Carolina University, Greenville, NC 27858, USA

  1. Changes in muscle strength, vastus lateralis fibre characteristics and myosin heavy-chain (MyoHC) gene expression were examined in 48 men and women following 3 weeks of knee immobilization and after 12 weeks of retraining with 1866 eccentric, concentric or mixed contractions.

  2. Immobilization reduced eccentric, concentric and isometric strength by 47 %. After 2 weeks of spontaneous recovery there still was an average strength deficit of 11 %. With eccentric and mixed compared with concentric retraining the rate of strength recovery was faster and the eccentric and isometric strength gains greater.

  3. Immobilization reduced type I, IIa and IIx muscle fibre areas by 13, 10 and 10 %, respectively and after 2 weeks of spontaneous recovery from immobilization these fibres were 5 % smaller than at baseline. Hypertrophy of type I, IIa and IIx fibres relative to baseline was 10, 16 and 16 % after eccentric and 11, 9 and 10 % after mixed training (all P < 0?05), exceeding the 4, 5 and 5 % gains after concentric training. Type IIa and IIx fibre enlargements were greatest after eccentric training.

  4. Total RNA/wet muscle weight and type I, IIa and IIx MyoHC mRNA levels did not change differently after immobilization and retraining. Immobilization downregulated the expression of type I MyoHC mRNA to 0?72-fold of baseline and exercise training upregulated it to 0?95 of baseline. No changes occurred in type IIa MyoHC mRNA. Immobilization and exercise training upregulated type IIx MyoHC mRNA 2?9-fold and 1?2-fold, respectively. For the immobilization segment, type I, IIa and IIx fibre area and type I, IIa and IIx MyoHC mRNA correlated (r = 0?66, r = 0?07 and r = -0?71, respectively).

  5. The present data underscore the role muscle lengthening plays in human neuromuscular function and adaptation

And actually I should say that changing a Type IA fiber into a Type IIB is impossible, but a type IA fiber can be made to express itself like a type IIA fiber. Also, ratios of fibers can be changed through the processes of hypertrophy and hyperplasia.

So, not actual transformation occurs, but the function of the slow fibers can change significantly.

I guess now that you have the answer to your question I can say…

Holy crap. I think this thread should teach us to be a little bit less condescending. Especially if our knowledge is based on “what we read/heard somewhere”.

Good stuff guys.

Pwned.

[quote]pocho wrote:
So, are there any workouts that can help to transform slow twitch fibers to fast twitch?[/quote]

Don’t worry about the content of your muscle fibers.

Train your nervous system and everything else will fall into place, especially for a beginner.

You could have all the fast-twitch fibers you want, but if you are sending a weak signal to them, nothing’s getting done.

So work with a lot of methods focusing on producing maximal force and power as well as the most plyometric activity of them all… sprinting.

[quote]jtrinsey wrote:
pocho wrote:
So, are there any workouts that can help to transform slow twitch fibers to fast twitch?

Don’t worry about the content of your muscle fibers.

Train your nervous system and everything else will fall into place, especially for a beginner.

You could have all the fast-twith fibers you want, but if you are sending a weak signal to them, nothing’s getting done.

So work with a lot of methods focusing on producing maximal force and power as well as the most plyometric activity of them all… sprinting.[/quote]

Spot on.

Damn good post.

[quote]RJ24 wrote:

For those who are interested, here’s yet another study:

Changes in muscle strength, muscle fibre size and myofibrillar gene expression after immobilization and retraining in humans

[/quote]

hahaha. Okay - I’m all for citing studies, and good ones at that, so could you please direct me to the information in this article that supports your contention that slow twitch shifts into fast twitch?

I’ll save you the time - that info is not there. If you’re going to use a reference, please ensure it supports your point of view.

cb.

Also, please try and not contradict yourself:

  1. Your original post:

[quote]RJ24 wrote:
Please don’t listen to this. This statement is so wrong it makes my brain itself hurt to read it.

You indeed can change slow twitch to fast twitch fibers
[/quote]

  1. A more recent post:

So which is it? Decide and then come back at me if you can.

The theory of hyperplasia is FAR from a proven phenomenon - so far only animal studies have demonstrated it (and have used excessive i.e. constant loading or huge numbers of eccentric muscle actions).

Good luck with your studies.

cb.