Referring to this article, I posted the following questions:

1) How long does it take for AMPk to become elevated with endurance training?
2) What sort of training constitutes “endurance training”?  Specifically, what sort of training elevates AMPk?
3) Could long resistance training workouts using higher rep ranges and shorter rest periods also elevate AMPk?

It is an older article (2008), so I thought I would post my questions here as well.

Pretty much any endurance training elevates AMPK as long as it is hard enough.. If you don’t push your self, it probably won’t get elevated that much.
I’ve seen everything from 1 hour long biking to 30 second sprints activate AMPK.

I would think high rep low rest resistance training could activate AMPK, the theoretical basis is there (increasing AMP) but I haven’t seen any studies on this.

How would 30 second sprints be different from sets of 10 to 12 deadlifts or squats?  It seems that if 30 second sprint intervals could elevate AMPk, then so could higher rep training of a compound exercise.  Any thoughts?

I think that short sprints may definitely generate legs hypertrophy as well as strength training

I don’t think AMPK has been shown to be activated after typical resistance training with 5-10 reps and 2 min rest periods between sets. I know of studies that hasn’t shown activation, but of none that has shown activation (except for in beginners, where it gets activated)

And one thing we need to look at is the energy required to do squats for 30 sec straight vs biking as fast as you can for 30 sec straight.

One study has found 4 bouts of high intensity cycling separated by 4 min rest to activate AMPK. Each bout took about 20kJ, which isn’t all that much.. but I have no idea how many kJ a set of deads would require.. thought that should be pretty easy to calculate. one sec..

140kg lift
1373N * 0.6m (the distance for me) = 824J per rep. So I’d have to do a lot of reps to get 20kJ (more than 20) of external work.

Now, I’m not saying you need x amount of work for AMPK to be activated.. but the intervals are more energy requiring than the deadlifts and AMPK is considered an energy sensing molecule.

Anatoly: That would probably have to be less than 30 sec sprints, as 30 sec sprints hasn’t been shown to activate any of the hypertrophy related pathways (to my knowledge) in this study it was found to not activate them:
http://jap.physiology.org/cgi/content/abstract/106/3/929

Also, if you sprint really fast, there’s the question of whether you have time to activate all your fast twitch muscle fibers (this would depend on the type of exercise, but with sprinting, every step is of pretty short duration, and I’m guessing most of the activity will be when you are actually touching the ground, which I think in some cases can be as low as 100ms)

Hey, Karky.  Thanks for the info.  That gives me enough information to shut me up (as I now see the difference between the amount of work performed in each of the different exercises).

As for sprinting, I belong to the Yahoo group “Supertraining,” and they often have discussions about sprinting.  I could be wrong, but from those discussions, I believe I have heard that ground contact times in elite sprinters can be as low as 60 to 70 ms.  Whatever the length of time, it is far shorter than the amount of time it actually takes for a muscle fiber to reach maximal tension (again, my information may be faulty here, but I believe the ground contact time is roughly half the time it would take for a muscle fiber to reach maximum tension).  I believe that developing strength in such athletes greatly helps to improve sprint times because the stronger muscle fibers can handle the great forces developed during faster running, but running fast doesn’t necessarily help to improve strength/size because (other than the acceleration at the start) most of sprinting relies on the stretch-shortening cycle.

Of course, the information above really applies to sprint running, but I am not sure how the body would be affected by swim sprints, cycling sprints, or something else.

I might be way off on this, but I thought I would share ... On the other hand, I would bet that taking an individual who has never performed sprint type training might experience some muscle hypertrophy when they first undertake such a program.

ALSO: I have no idea why I posted this in the “Nutrition” forum.  Doh! 

yeah, it’s possible it could be lower than what I said. 100ms was pretty much a guesstimate.

3) Could long resistance training workouts using higher rep ranges and shorter rest periods also elevate AMPk?

Dan More from HST had a training program based on this concept. He suggested resting between reps to minimize AMPK accumulation and thereby increase muscle. I think he doesn’t talk about it much anymore.

Maybe if you are doing 25-30 reps, you might see an increase but I don’t think it will be anywhere near what endurance training can do.