Could the less-is-more approach to marathon training be the way for me to get good for age times? Using aerobic cross-training to feed the intracellular bacteria that fuel my cells and my running addiction…

I’ve neglected this blog shamelessly for a few weeks because work is an irritating distraction.

And today I’m going to take it in a different direction.

Because I’m ridiculously ecstatic!

After 8 ish months of chronic left thigh injury/ ‘soreness’, I managed my first half-marathon in a year in 1 hr 44 mins and 46 seconds.

It’s not a PB, but it’s not far off, and its a lot faster than I was expecting.

Because I’ve only been running 3x a week since my injury at the end of January, plus training for a 5k swim by swimming distance/sea swimming against a current 2 or 3 x a week. And it seems to have done the trick.

I’m nearly back to where I was on almost half the run training. And I hadn’t even dared run a sub-eight minute mile for more than 3 miles in training….

Yay. My ego is boosted (it’s all vanity, as a song by that name says, but I don’t care right now), my confidence is increased, and I’m thinking seriously about my next attempt at a sub 3.45 hr marathon. I’m after a good for age time for London marathon. I was 6 mins off thanks to nausea in my last attempt a year and a half ago and this year I’ve been injured.

So next year I really want it. Now even more.

Previously I have been an obsessive slave to getting the miles in then running a few more for good luck. It didn’t work for me. My hamstring spat its dummy out (or did it? That’s possibly a topic for another day) so I’ve got to do something different. I’m hoping this it it….

So what’s going on?

And do I dare risk substituting some easy runs for long, aerobic swims in preparation for the marathon? Because that’s got to be better for my grumpy leg, surely?

But is there evidence to suggest that cross-training like I have works?


It’s all about getting that aerobic stimulus.

However you can.

And as you age, it seems running less but running quality could be the way.

Aerobic training and mitochondria

(Sadly, I don’t have access to an electron microscope so this is from Wikipedia commons)

I’m a biology teacher, so I like a bit of scientific evidence. And there’s a body of evidence to suggest that aerobic exercise of any kind increases the production of mitochondria.

Mitochondria are the small structures in our cells that carry out aerobic respiration. They use oxygen and pyruvate (from glucose/fats) to generate the ATP all cells require for energy.

(Thanks to sciencegal4.0 for this one on Wikipedia)

Mitochondria are actually bacteria!

Or they were!

Our cells rely on a symbiotic relationship with ancient bacteria and without them we would be dead!

Or never have existed.

The thing about bacteria (I used to be a microbiologist) is that they will only copy themselves to increase population size when there is an environmental signal to do so. Conditions have to be perfect. There’s no point increasing your population size otherwise, because you’ll all die from lack of nutrients/metabolic byproduct accumulation/both.

And what’s the environmental signal that mitochondria respond to?

Actually, I’ve found no research on that as yet.

It could be pyruvate levels as this is what mitochondria use in the Kreb’s cycle.

It could be oxygen.

It could be the break-down products of ATP! If these accumulate it would signal that there is a need for more energy…It could be all of the above or something unheard of. Who knows. Mitochondria are the ‘descendants’ of archea. Some of these things can make ATP from sulphur…

Whatever the signal, mitochondria definitely copy themselves when you do aerobic exercise. They also grow, so not only do you have more of them, they have more space to carry out aerobic respiration. The upshot? You get more ATP, meaning more energy and more muscle contraction. In addition, aerobic stimuli make them repair themselves more efficiently. They also form a more structured matrix and dead ones are cleared more effectively.

(Refs from a review by Dr Bryan Meyers on though I have read numerous primary sources on this topic since I got into running. I’m too lazy to go and find them all again now I’ve decided to write a post about this).

What gives you a sufficient aerobic stimulus?

Running long distances relatively slowly is, of course, an excellent aerobic activity.

The long run is also essential for making your capillaries grow, so improving blood flow and oxygen supply. Without capillarisation, you’re going nowhere, because there’s not going to be enough blood to get oxygen to your muscles, so you won’t make enough ATP to move the muscles. In addition, running uses and strengthens the muscles you need for running. So, there’s no getting away from doing long runs (if you even want to! I don’t, I love them), but it does seem that you can top up your aerobic exercise with cross-training…..

Crosstraining options

Apparently, the best cross-training for runners is cycling.

Sadly, cycling (for triathlons) seems to have partly triggered my leg issues in the first place. So, cycling is not something I want to risk just yet.

So I’m thinking of keeping up my longish swims over the winter. I’m a lazy swimmer. I love it, but I truly can’t be bothered to try to go fast. My swimming only verges on anaerobic when someone forces me to sprint or do backstroke. (I hate backstroke, but they love it at the swimming club I go to and they force me to sort of sprint too).

I’m assuming that these long swims are what’s given me the extra aerobic fitness to run sub 1.45 comfortably. I’m hoping that as I increase the long run mileage and tempo/interval session length that the fitness for sub 3.45 will come together.

And if it doesn’t, there’s always 2020.

Maybe my left thigh will stop niggling one day and I can go back to running 5/6 days a week, but I’m hoping quality topped up with swimming will do it for me….

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