Part III

"Can you please take the time to explain why my 2 hour run at 8 minute per mile pace was significantly harder than my previous week's run of 14 miles at 7:40 pace?" – Flagpole Willy

This next part was not even planned to be included when I began this thread, but I had a thought that Flagpole’s 8.00m/m run was going to be harder for him than his 7.40m/m, and I knew I had a personal experience that should explain to him (and perhaps others) why this might have happened.

I will start therefore with a personal anecdote and then explain why things occurred as they did afterwards.

11 March, 2003.

I have always ridden motorcycles. I tend to ride them pretty hard. I live in a rural area, so this usually means throwing the bike like a maniac round the twisty country roads. Great fun. The part of me that loves doing this has not aged one whit. All this just to explain that occasionally I come off the bike, sometimes spectacularly.

One such time (and not the last), almost 8 years ago, involved some broken bones and a prolonged spell out of training. It was six months before I felt like getting back into it, and when I did, it was winter and miserable. So I postponed it some more (which was suprisingly easy to do).

When I did go out for the first few runs, they were a major struggle and I could not remember ever running so slow in my whole life. I had still been coaching all the while I was out of running, and had recently started a couple of new young guys. Although I tell them I really don’t care what training they have done before they come to me (and that I was going to test them myself and form my own opinion), they (and others) are pleased to show me their old training schedules and often show up to first day of training with a printout. (It usually turns out they are mad keen to show me how fast they can run a session of 400s).

Perhaps because I was browsing some of these printouts, added to the depressing fact I seemed to have slipped back so far in what was now one whole year off training, but I decided to try something a bit different. I am nothing if not a student of the sport, I knew how I coached, and what worked for me, but I also knew there were many other ways that claimed to get you fit. I had read all manners of training schedules over the years. So I decided to put myself on a low mileage/high intensity schedule and hammer my old ass back into shape in the shortest time possible. What can I say? It suited my temperament at the time.

I formulated a week that included; a 3-mile run as fast as possible (and trying to improve the time each week); a 45-min hilly route run as intense as I could make it; and a 90-min run at best possible steady pace (without struggling or crashing and having to back off at any point). Three other days were just 30-45 mins at a reasonable lick. No slow easy runs in the whole week. One day a week off.

I kept this up for 3 months. Along the way I took part in some shorter faster stuff with the younger kids during training. I realised though that there were some days when I just could not keep up the pace on the 45min or 90 min runs in training, and would just bag those runs and turn for home.

A year previously, I had been used to long runs with the 2.35-2.45 marathon group, but I was now acutely aware that I could not yet go back out with them, but I did accept the good-natured cajolling of the 3.00-3.15 marathon group to join them for one of their 2hr+ long runs (±8.00-8.15m/m).

Now, as all runners do, I had already figured out that my 3-milers were by now at 5.30-5.40 pace, the 45 min run was 6.00m/m± and the 90 min run was somewhere around 6.40m/m or so.

Even the easy runs were rarely slower than 7.00m/m. You would have thought 8.00m/m would be a breeze…

It was one of the worst runs of my entire life. I can still recall it. All the way I wanted to either stop and walk, or speed up to normal 90-min pace and get my ass out of there. The rest of the group were laughing and joking and I was gritting my teeth because it felt like my legs were made of wood and someone had tied a piano to my back. Luckily, I was not too suprised and I knew why I felt so bad…

Way back in the late 1960s a professor called John Holloszy got some rats to run on a treadmill for various lengths of time up to 2hrs per day at around 50-75% of the rats’ VO2max (easy running, therefore). After 12 weeks, he found that the rats had increased the mitochondria (vital for aerobic energy production) in their running muscles (compared to control rats that did no training). This was a seminal piece of work, because it explained why runners get better with training.

The next question was logical. How long should people run for to optimally cause this effect?

Back to Holloszy and his fellow researchers who formed 4 groups of rats to train: one group running 10mins/day, a second running 30mins/day, a third running 60mins and a fourth running 2hrs/day. All at the same easy 50-60% VO2max, and for 5 days/week for 13 weeks.

Perhaps logically, the 2hr-group had the greatest increase in mitochondria at the end of the training period.

In a tough endurance test at the end of the training, the 10-min rats managed 22 mins, the 30-min group 41 mins, the 60-min rats could run hard for 50 mins and the 2hr-rats kept going for 111 mins. It was now apparent that time to exhaustion (all rats running the same pace) was directly related to mitochondria development (which itself was directly related to time spent training).

But what about intensity? Were mitochondria only created while running long and slow?

In 1982, a guy called Gary Dudley decided to explore this question. He had several groups of rats training five days/week (but only for 8 weeks). Like Holloszy, he also used a range of different training durations, from 5-90 mins per day. However UNLIKE Holloszy (whose rats all trained at the same pace) he also used a range of training intensities. Dudley’s rats trained at either 100%, 85%, 70%, 50% or 40% VO2max. He also examined how different intensities and different durations affected different muscle types (fast twitch white, fast twitch red or “intermediate”, and slow twitch).

The results were interesting and each fibre type responded differently:

Improvements in mitochondria in fast twitch white fibres began while running at 80% VO2max (but not slower, presumably because they were not recruited) and increased exponentially as the pace climbed to 100% VO2max.

However improvements in fast twitch red (intermediate) fibres maximised at sub-max paces (85% VO2max) and did not get better with increased speed.

And the best way to cause improvements in slow-twitch fibres was to run long and slow at 70% VO2max (adaptation began from as low as 50% VO2max pace). Faster was not better. Although Dudley found that 90 mins was not better than 60 mins, Holloszy had shown that 2hrs was definitely better than one hour (which ties in nicely with Lydiard-type training recommendations that one 2hr run was better than 2 x 60 mins — you have to admit that the guy had great intuition born of his experience trying out different training on himself).

So, (some of you may be way ahead of me already). Why was my 8.00m/m run so difficult?

Well, all my training in the 3 months leading up to it had been relatively hard. I had not trained slow enough for my slow twitch fibres to become stimulated to build huge amounts of mitochondria. My fast twitch red were becoming okay (I was reasonably good for 3-6m fast), but I could not access those fast powerful fibres at 8.00m/m. The intensity was too low. I was being forced to use my slow-twitch fibres… and they were not trained for any kind of endurance, and certainly not 2hrs.

It seems paradoxical, that I can be okay at 7.00m/m, but not at 8.15m/m, but here is one example.

I was okay if I ran hard enough to force my body to recruit my fast twitch red fibres (and as long as they had enough glycogen). Like most distance runners I have relatively few fast twitch white fibres, so they were little help, and in all my 3 months of training my slow twitch were being bypassed on every training run. (Or rather, recruited, but swamped/overworked). The intensity of each training run was too high for them to be stimulated optimally to best create mitochondria in themselves (and thus improve). So when I ran at a pace that I was forced to access ONLY them, I was sunk.

Following this run, I threw out the intensity and went back to training sensibly. In 10 weeks I was more like my old (younger?) self.

So, to sum up:

To improve your LT (which will have a direct impact on your race performances), you must increase the mitochondria in your running muscles (in a neat move, the optimal training to improve mitochondria is also the optimal training to improve capillary density).

The more mitochondria, the less lactate at every running pace. But mitochondrial adaptation in each fibre type is training-intensity dependent. If you want to maximise the number of mitochondria in each fibre type, you must train at the correct pace for that type. (remember; the more mitochondria, the less lactate; the less lactate, the faster the racing pace and the more economical you are at any pace, meaning you can keep that pace up for longer.)


On to Part IV

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