How fast do we lose fitness?

The topic of detraining has come up a lot, lately. At the time of writing this, we are under a stay at home shelter and our spring marathons have been cut short. A lot of folks feel like their hard fought gainZ are lost forever. However, I feel like there is a fair amount of confusion regarding what detraining is and what variations we typically encounter with training. So, today, let’s discuss what is really going on and if those feelings of having to start over are really warranted.

First, there’s full fledged detraining.

This is stopping training all together or reducing so much that a training stimulus is not elicited. This is what you’ll see a lot of blog posts and articles reference and when we talk about “use it or lose it” we are referring to this. The end result of detraining is loss of fitness over a period of time.

The second is the taper.

This is interesting because some folks buy into a very long taper and can actually dip into detraining if they reduce it for long enough time. That’s a discussion beyond today, but an interesting thought to expand on.

The purpose of the taper is to improve performance through rest.

I would define it as a calculated reduction in training through volume, frequency, and intensity, to maximize race performance through realizing the improvements made in previous training.

Third, we have the maintenance.

This would fall between complete detraining and taper. It may or may not be planned, as it may be done to try and mitigate downtime for injury, or, in our case, there’s no race to train for! With maintenance, the training stimulus is high enough to stop the downward trend of fitness loss (or at least slow it). However, it’s not high enough to promote further fitness development. I like to describe it as treading water.

The last one, to me is early rebuilding mode.

Some would refer this to reverse tapering, but I tend to stay away from that term. That would suggest that I am going to taper for may race, run the race, then follow my taper plan in reverse to get back to full training. However, I wouldn’t do that to my athletes! I couldn’t imagine giving an athlete a 10 mile tempo 10 days after their marathon! Early rebuilding, for me, would be the time post downtime (due to injury, illness, planned time off, or race) that takes us from reduced fitness to normal training volume and intensities. How I would approach this would vary on individual circumstances. This is one we will have to talk about later, too.

For now, let’s focus on detraining and maintenance.

During this time of forced shutdown, people have gone from peak training to forced downtime. Like I mentioned, there’s a lot of worry about “starting over” or at least losing a significant amount of fitness. The general consensus is that with a short amount of time off, performance will actually improve performance, but go past a few days and performance will start to decline. Specifically:

After 2+ weeks, VO2max decreases. I’ve seen a lot of numbers, but generally, 5-20% depending on time off.
Ventilation increases 10-14% within a few days. This would make exercise feel harder after a short amount of time.
Lactate Threshold starts to decrease after a few days off.
Capillarization decreases to pre training levels within 4 weeks.
Mitochondrial enzymes decrease 25-45% for up to 12 weeks.

There are others, but the point is made. If you go full stop on training, you will begin to lose fitness. In terms of performance, what would that mean? After 3 weeks off, your times will slow 3-5%.

What’s that look like on the clock?

40 minute 10k: 1:15-2:00 slower (Ouftda!)
1:45 half marathon: 3:00-5:15 slower (Yikes)
4 hour marathon: 7-12 minutes slower (Ouch!)

So that is pretty scary to think about!

However, remember that it is completely shut down.

If we are able to not train as hard or as often, but still getting out there, what’s the damage? If we reduce training, we can maintain our physiological gains and maybe even maintain a very high level of performance over a much longer period of time. On top of that, give our body a much needed break from our heaviest of training.

I looked at three articles regarding reduced training in distance runners. Now, to be fair, these studies were all pretty small in subjects and they were with younger runners. So, take it as you may! With the three studies, there was a period of normal training period followed by a 2-4 weeks block of reduced training. Peak mileage varied, but reductions were 50% to 70% in volume Frequency was also reduced. Intensity varied.

The results were pretty similar.

What was found is that there was a maintenance of primary measures. VO2max, running economy, and lactate threshold all held steady. From a physiological standpoint, we see no changes. However, in two of the studies, performance via 5k times were unchanged. In another, one was slower after the reduced training. However, it is important to note that body fat increased in these subjects from 10.4% to 11.8%. If you were to weigh 150 pounds, that’s an increase of over 2 pounds of body fat. It might not seem that much, but if the adage of 2 seconds per extra pound, that’s 4 seconds per mile, at least.

More importantly, it gives us a clue to our own training reduction.

Physiologically, we may be holding steady, but our weight can certainly fluctuate in a time of reduced training- not that I am speaking from personal experience, or anything! It just goes to show how much nutrition will play a role in all we do!

I did look at a fourth article that was similar to the other three but looked at testosterone, cortisol, and creatine kinase. With testosterone, runners were on the low side during regular training and unfortunately, the levels didn’t improve after the three week reduced volume. I don’t find this as a surprise because rebuilding testosterone (naturally) is a long term process- months of diligence. Cortisol, which is a good marker of stress levels, was also high during the regular training block, but also didn’t change significantly with reduced training.

With testosterone and cortisol, this is just a good reminder that we have to control for these long term and that we have to look at nutritional supplementation if we are going to go big ripper in training.

Lastly, creatine kinase was also high during training (expected), but this did drop significantly during reduced training. Hooray! CK is a measure of muscular damage, so this shows us that we can maintain fitness while allowing our body to recover. Anyway, just something I found interesting while looking through research.

Ok, now the question remains- what is the best way to maintain our fitness?

Glad you asked. There’s three things we can do.

The first two are reducing volume and frequency.

This may come from reducing the frequency to reduce the volume and get a twofer. Or, you can simply reduce the volume of your runs. Personally, I like reducing by 25-35% of my volume. I typically keep the same number of days, just reduce the volume. I will reduce the days if the person wants to cross train instead of an easy day.

Now the third variable is intensity.

This actually needs to stay the same or even increase! This means that easy days remain within your easy range, but more importantly, you shouldn’t abandon doing workouts completely.

Now, instead of doing two SOS and a long run per week, you may cut to one SOS and a long run.

The long runs should be reduced in volume, but if you run these in your moderate to long run range- keep em there. For a weekly SOS day, you can skip the marathon tempo every week. Depending on the break length, I usually just rotate different workouts. However, faster workouts show more promise in maintaining the physiological levels. So, this means keeping LT, 5k/10k repeats, and even mile pace repeats in the rotation. This works out well, because the volume of these are less and fit in better with the reduced volume.

Here’s what a sample for weeks might look like:

Week #	Monday	Tuesday	Weds	Thurs	Friday	Saturday	Sunday
1	Easy	Off	10k Reps	Easy	Off	Long	Easy
2	Easy	Off	5k Reps	Easy	Off	Cutdown	Easy
3	Easy	Off	LT	Easy	Off	Long	Easy
4	Easy	Off	Mile reps	Easy	Off	MP	Easy

Super simple maintenance plan. LT= lactate threshold MP= marathon pace.

You could honestly repeat this for a couple months, be fully recovered from hard training, maintain the vast majority of your fitness, and then pick up a new training segment for any race distance. The big point of all this, is don’t be scared of scaling back your training. Done the right way, you’ll come out of this a better runner for the long term.

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