Muscle glycogen - train low, race high!

Paul Kayley · 05-27-2007, 05:04 AM

Muscle glycogen depletion in the recruited muscle fibers used during a specific endurance activity is a powerful trigger for endurance adaptations. The latest recommendation on the endurance grape vine relates to muscle glycogen - "Train low and race high!"

This makes a lot of sense to me. Although getting the balance right is critical to avoiding over-training and stalled adaptation.

Mike ODonnell · 05-27-2007, 08:04 AM

Makes sense as you carb load before a race....so you are not going to train in hyperglycemic state....always good to train harder and then make the race easier...train single speed, run with resistance/up hill, etc....

Greg Everett · 05-27-2007, 10:49 AM

paul - how depleted are we talking here?

Paul Kayley · 05-28-2007, 02:46 PM

Hey Greg, thats a very good question. IMO&E, total depletion at the end of a training session would be counter productive, as it would be a taking the stimulus a couple of steps too far, resulting in cell damage and the need for prolonged recovery.

The volume and intensity of the training used would of course depend upon the fiber range being targeted. It is quite easy, with experience, to feel the point where you start to near the 'bottom of the tank' in terms of muscle glycogen(MG). This is the point in a training session where I start to back off. Going home feeling tired but not completely wiped out. The term 'train low, race high' isn't suggesting training in a depleted state, it is discouraging continuously and repeatedly carboloading the cells.... this just gives the athlete more work to do in order to stimulate change. Its training with a constant tail wind!

It might be worthwhile mentioning that the MG stored in a single muscle cell is locked in that cell, exclusively for that cell's use. It cannot be accessed for use by other muscle cells or to bolster ebbing blood glucose levels. This also means that the stimulus of MG depletion is also cell specific.

I've probably missed loads out, so ask away if I have... thats a rushed answer as I'm rushing about!

Greg Everett · 05-28-2007, 03:32 PM

Interesting... Looking forward to reading more on this.

Derek Simonds · 05-29-2007, 02:59 PM

I have been thinking about your post for most of the day. If you are an endurance athlete that eats a mostly paleo / low carb diet are you already on the low side pre-exercise?

I did a 2 hour ride with my sister on Saturday that turned into a little more of a hammer than originally planned as we rode out with a 20 knot tailwind. Oops! I definitely was at the "bottom of the tank" when we got back. I ate my normal meat, salad and small amount of carb meals for the remainder of the day. Sunday morning we did a 45 minute high intensity ride with a 20 minute tempo transition run. It ended up being a pretty tough brick. Afterwards I couldn't eat right away but when I could I was ravenous.

What made me think about this is how I was eating in the past when constantly training for triathlons. It was definitely more carb focused. Today I train 3 days a week endurance and I don't feel like I need the extra carbs except Sunday when I was so hungry I could have ate the paper plate my food was served on.

This also played into a question that I was going to ask Paul. On my heart rate monitor during the Saturday ride it showed that I burned 1734 Kcal's. Is the only factor in determining calories burned average heart rate over time? I am sure there is some algorithm that the watch uses to calculate the calories burned, but does muscle glycogen depletion come into play for calories burned?

Meaning if I worked out for 1 hour and felt near the bottom of the tank at an average heart rate of 140 and the monitor showed 900 Kcal's versus working out for 1 hour at an average heart rate of 140 but not feeling depleted did the first example actually burn more calories?

I hope this made some sort of sense, as is appears I am rambling again.