I think I read something by Daniels that said that once you have undergone a period of cardiovascular training you will retain 80% of the related aerobic efficiency no matter how long you take off.

Certainly you won't lose any fitness in a few days.

quote:<HR>Originally posted by bigapplepie:
I think I read something by Daniels that said that once you have undergone a period of cardiovascular training you will retain 80% of the related aerobic efficiency no matter how long you take off.

Certainly you won't lose any fitness in a few days.<HR>

My previous reply doesn't appear so I'll summarize what I wrote...

I'll respectfully disagree. What I've read indicates that the half-life of a mitochondria is around 15 days and that when the stimulus is removed up do 30% of them go away within 10 days. I wouldn't say these numbers are exact, but essentially it says that within at least a week or two you do indeed start to lose your aerobic fitness.

Your post says "efficiency" so you could argue we're arguing different things since I am talking capacity...however capacity has a greater impact on overall running ability than efficiency.

I don't know of any research on capillary beds though I'm sure it exists. I'd bet they last months rather than weeks.

If you are training hard, you are never fully rested. In fact if you DO feel fully rested then you really aren't training as hard as you could and still make gains.

Just because you feel a little fatigued does not mean you aren't making aerobic gains. This "felt" fatigue is mostly muscular. As long as you aren't over-training, you can indeed feel tired most days while making aerobic gains. It's a balancing act that requires a lot of experience to balance correctly.

What this means is that if you are training to maximize gains then you will not be able to race well because of the residual muscular fatigue. Likewise, if you are in peak racing shape you've probably ceased making large aerobic gains during that short interval.

You "feel like a million bucks" because you rested and do not have the muscular fatigue that you are used to. However, if you really want to get good you don't want to feel this way all the time.

In the month prior to running my 10K PR, I ran a HM PR (1:09:53) followed by weeks of like 120-100-105 miles. I was ALWAYS tired during this interval. I could not have raced well during these weeks as I was always tired. Following those weeks, I cut back to like 45 miles leading into my 10K. All of a sudden my last tempo (4 miles @ 5:13) felt pretty easy. But even that was not a good predictor of the 30:57 I ran 4 days later when fully rested. While I had AVERAGED under 5min for 2 miles previously I had never run two consecutively....and all of a sudden I put 5 of them back-to-back. It's amazing what a little rest will do....but it took training a little tired all the time for almost a month to get there.

Edited to add: bigapplepie is 100% correct that you are comparing apples to oranges with regard to weightlifting. It is standard not to lift the same muscle group on consecutive days to allow fatigue to go away...but this is MUSCULAR, not aerobic. In running we are more concerned with aerobic gains as long as muscles aren't OVER-trained. This is why you taper into key races...to clear the muscular fatigue. But you can't do this all the time during training or you sacrifice aerobic gains.

http://This message has been edited by AndyHass (edited May-29-2007).

The common stat I keep hearing from coaches is 1% per day.

If you take 5 or 6 days off, then do a short workout with some at race pace, you can really fly the next day! Can't do that too often, of course, or you will lose conditioning, but an important race it's well worth trying.