Fast-Twitch VS Slow-Twitch - JP Fitness Forums

Danagrrl · 08-28-2005, 02:27 PM

Discuss.

Is this the reason I too, can run for hours slowly, but feel like I will die in short sprints? Anyone think that the short steep uphills with full recovery between are a good way to go to improve my speed?

Buk · 08-28-2005, 07:45 PM

I would guess that you have spent more time training to run distances than sprints. A slow twitch versus fast twitch dominance might keep you out of eliete ranks for the one of which you are not. But it is very extriemly highly likely that any predisposition you have is NOT the reason sprints are difficult. Sprints make you want to die because of the relative amount of effort you put into them. Your long runs would make you want to die if you did them long enough, or a little faster. This tells me that you haven't pushed yourself on a distance run in quite some time. Sprinting IS harder though. There are about 500,000 recreational marathoners in the US, but the number of recreational 800 meter runners is much less. Sprints are harder and less fun for the general public.

Hill repeats will probably improve your speed and so will running sprints. Distance running will have little or no effect on your sprint speed. But sprint training can improve your distance efforts by improving running economy, VO2, and lactate threshold.

newride · 08-29-2005, 10:52 AM

I'm really hoping Buk is right. Otherwise I have been beating myself up with the HIIT for the last few weeks for nothing. I really don't care how fast I can sprint, but if it helps my longer distance time than I am all for it. I actually haven't done anything but HIIT for quite a while so am looking forward to taking a longer run to see where I am at now compared to before the HIIT. This week I did change it up a little by using a watch to time 30 sec intervals. This kept me running longer (and resting longer) than the pole to pole method I was using earlier. Don't know if I like it more or less but will try it out a few more times anyway.

Danagrrl · 08-29-2005, 01:38 PM

you nailed it--I am a distance runner, full of endurance and no speed. I have "plateaued" since (ugh) March and have been trying to figure out why. I need to kick it up.

are Tabata runs good for increasing speed as well? any other ideas? I feel like this is where I need to expend my efforts now, not on mileage.

Danagrrl · 08-29-2005, 01:40 PM

one more thing, you wrote:
"But sprint training can improve your distance efforts"

can it also make my miles faster?

Buk · 08-29-2005, 07:15 PM

Gains in any sport/activity are easier to make, the worse you are. It is easier to knock a minute off of your mile time if your current best is 10 minutes than if your best miles is 5 minutes. It is easier to move up 3 rankings in the world tennis rankings if you are in the 300s rather than in the top 10. Sometimes people see this as a plateau. They go run a moderate 5 miles every few days and get noticably better for quite some time. But there comes a point where getting better requires a lot more effort, it isn't a plateau, it is an equilibrium. Now to get better you have to work harder and with more intensity.

When you ask about speed increases what distances are you talking about?

Dr. Tabata's major study that introduced his intervals to the world was a very well designed and run study. He used fit athletes rather than couch potatoes who will respond to any stimulus. His results showed that aerobic training does not improve anaerobic capicity, but that the Tabata intervals increased anaerobic capicity by 28% and increased VO2Max by 14%. This will have a very positive effect for short and long distance efforts by improving how much oxygen the body can take in and utilize. Basically VO2Max limits your aerobic capicity, increasing intensity beyond VO2Max draws a majority of energy from anaerobic pathways which will severly limit the sustainability.

Another variable in the equation is Anaerobic Threshold, also called lactate threshold. It is usually considered more trainable than VO2Max, even though Tabata's subjects increased 14% on fit athletes. The anaerobic threshold is the point at which your body cannot remove blood lactate as fast as it is being produced. This is a lower intensity than your VO2Max, 55-60% for untrained people, up to 90% in the elite. If you are exercising at or below lactate threshold, blood lactate will not accumilate.

I have not seen any measurements that Dr. Tabata took on lactate threshold during his study. But they might have been misleading with such a dramatic improvement in VO2Max. Improving your VO2Max and lactate threshold is what will allow you to run at a higher intensity(faster) for a given amount of time. Along with improving running economy, that is how you get faster.

I am not sure if I addressed any specific questions. I wrote this intermingled with working today and I think I rambled a lot.

Danagrrl · 08-30-2005, 11:13 AM

this is very helpful, thank you.

(btw, my mile SLOW...believe me, I have much room for improvement.)

T-Runner · 08-31-2005, 08:39 AM

You've gotten some great and helpful advice thus far. I just have a couple more things to add.

First, hills are a great way to improve your sprinting speed, as are short repeats. However, they will only help your distance training if you spend enough time over the course of a training run at your VO2 max. The only way to improve the VO2 max is to run at your VO2 max. Therefore, you need to either: A.) Run longer intervals that force you to hold a tough pace for a longer time or B.) Run short repeats without full recovery between them so that your body never returns to its VO2 rest level. This will get you back to your VO2 max quickly during each repeat and cause you to spend more total time at VO2 max. or C.) Use a combination of the above types of workouts during a week. Option C will probably prove most beneficial.

The best, most scientifc resource I've ever found on running is Daniels Running Formula by Jack Daniels. I recommend the book, but a simplified overview can be found in a series of articles through the following link: http://www.coacheseducation.com/endu...ls-nov-00.htm. The article I've linked you to is actually the fourth in the series, but it has links back to parts 1, 2, and 3.
Good luck, and enjoy your running.