Photo courtesy of Andrew King - D4 Productions

Saturday, February 6, 2010

26 myles - 3.03:18

HR urban trails - 8 A.M. and 2 P.M.
mid 40s, partly cloudy, dry trails and road
mind/body - good
easy effort

I was supposed to get up this morning to have enough time to crank out a 3 hour run before Jaxon's basketball game but I slept in again. So I decided to make this my first ever 2-a-day: morning 8 myles - 58:04/7:15 avg., afternoon 18 myles - 2.05:14/6:57 avg. for an overall avg. of 7:03. The last mile this afternoon I decided to test the leg speed with a 5:50 split. Since I faded in the marathon I'm gonna try to do more of the speed stuff towards the end of my runs, hopefully it will help.

Now that I've done my first ever 2-a-day I am now wondering if there are any studies to determine which is more beneficial; 1 run for 3 hours or 2 runs 1.5 hours each. Anybody know? And when I say beneficial I'm specifically speaking of glycogen stores.

7 comments:

GZ said...

Lots of back and forth on this topic. Obviously if you can absorb it in one gulp, the training benefit is greater but ... it needs to be taken as part of a greater picture. Is the athlete going to more likely to be hurt with the one big session, or can they absorb more with doubles (both on the day in question and the next day).

Since you are more likely to deplete glycogen stores in the one run (as you are more likely to eat b/w 1st and 2nd run), it comes down to what you are training for ... feeling out what it is like to run on depleted stores, or coming back for a second run more recovered.

No help here ... Sorry.

Stuart Swineford said...

You certainly do know how to make a fella feel slow. ;)

Nice runs. Keep it up!

~stubert.
http://www.runsturun.com

Unknown said...

I think 2-a-days are more of a mental challenge than anything else. My day was basically planned around them to include eating.

Good insight GZ, I'm gonna do some research.

JC said...

Howdy Scott, I have held onto this link for some time now and think this may be relevant to your question - or at least in the right direction. Enjoy!
http://pfitzinger.com/labreports/twoadays.shtml

Jon Allen said...

Scott- this doesn't specifically address glycogen, but it is a good post on doubles.

http://fastrunningblog.com/forum/index.php/topic,228.0.html

My general view is that, for endurance purposes, doubles can't replace a long run (i.e. 2x1.5 does not equal 3). But I usually run doubles 3-5 times a week during high mileage times since it allows me to do higher mileage with lower risk of injury.

That being said, 2x1.5 is better than 1x1.5.

Just my uneducated opinion.

Anonymous said...

A question that is related is how much of a break can you take in a long run and still reap the same benefits of not stopping. i.e., what if I go for a 20-miler and take a 10 min break for water and stretching 1/2 way through. Does that negate the training effect? Scott - have you been able to dig up any science on this yet?

Unknown said...

Hey Anon,

Absolutely you will gain the benefits of the entire workout as if you didn't take a break at all. And I'm speaking only from a glycogen depletion perspective. For me I'm interested in as much depletion as possible because during an ultra that is what happens.

Science wise, it's a well know fact that muscle glycogen restores at a rate of 5%/hr and muscles are usually more receptive during the first 15 mins after exercise - it takes roughly 24 hours for full restoration. So by stopping, replenishing I believe you are teaching your body to assimilate glycogen more efficiently.

In the end, if you run 20 myles, stop for 3 hours, then run another 20, I think that would be the same as running 40 altogether - from a glycogen perspective.