Ninety minutes

Let me share a recent thought. Bear with me - this may ramble!

I went on a long run with my club yesterday. It's nice each weekend that there are several groups of runners (each with a leader) offering runs at different paces and distances, usually with cut-offs built in for people to bail out when they've done the distance they want.

There are a lot of people training for marathons at the moment, so a lot of the runs are pretty long. The group I went out with were planning for a maximum of 16 miles, and I (and another runner) decided we'd do 11 or 12 miles, which is what I've routinely doing through January and February.

I found myself feeling the pace and struggling with tired legs at one point - not out of breath, just tired and heavy legged. The other 11/12 miler told me later she'd felt the same. Happily, it passed and I started to feel stronger again.

Then our leader admitted he'd got a bit muddled with his route (this was after 11 miles) and we were about 3 miles or so from the sports centre which is our base. Rather than bail out, walk or call for help, Emma (the other runner) and I agreed we'd keep gently running back. She was quite excited at the prospect of doing 14 miles!

We did - I saw us go through a half marathon in 2:30, and we got to 14 miles a little way from the centre. Emma told me to go ahead - she was going to call it a day and walk. Shortly later, I heard her calling me, and saw her jogging towards me. She said it hurt more to walk than to run!

We got back with a distance of 14.48 miles, a new PB for both of us, and our second fastest half marathon!! The other runners completed their 15/16 mile runs - not much more than Emma and me!

Our very own Nick (Wristy) is also training for the London Marathon. Yesterday he did a 15+ miler (good on you, Nick!) In the comments about his run, he described having a "major crash" after about 7 miles, which he got through and then felt better.

That got me thinking. I looked at his splits/cumulative time, and seven miles was after 90 minutes running. I looked at my run, and my difficult patch was - about 90 minutes in!

How long can the average runner run using the readily convertible glycogen stored around the liver and in muscles?

Ninety minutes.

Now, for some time, I've been aware of the need to refuel on the hoof, and I'd been doing it - a Shotblok after the first half hour and every half hour thereafter. However, I wonder if the body starts to adapt its metabolism (aerobic to anaerobic?) once the glycogen's gone, so it's doing a bit of a mixture. What if, as new runners, or especially new to distance runners, our body isn't very good at it? Perhaps, with training (plenty of long runs) our body gets better at it. It's a hope. But I think simply stuffing in the fuel on long runs won't always avoid the "bonk"/wall/crashes. In time, with luck, it won't happen as much.

Anyway, that was my last long run for a while - it'll be a moderate medium long run next weekend as I taper - the North London half a week on Sunday, then the White Horse half two weeks later!

I hope all that wasn't too boring. I find myself fascinated by the science!

That run -

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11 Replies

  • Keep at it Steve, as a spectator from the IC I can see you doing a Marathon this year.

  • Definitely not this year, Phil, but I'm harbouring a faint ambition for next year!

  • Well done Steve, personally I've no intention of running more than 10 miles and will only run 10k's or 5k's competitively

  • The half was a real blast - 5 and 10ks are over so quickly!

  • The ninety min thing. I have had to be aware of that for a while now. I'm a slow runner and until recently it took me 90 min to do 10km so for most of my HM training last year I really had to work at getting past that 90min thing. Because I am slower I worked out that 1/2 a jelly baby at 5km then 1/2 every 2.5 km after that kept me going all the way up till 21.1km. If I go out for a 90 min run now I don't take anything only if I go over that do I start to think about it.

    Well done on that run though what a great achievement great time and pace.

  • Thanks, RFC. I was pleased with that run, because I wasn't broken at the end of it. I came down with a bump today, though - went for a 12k run and it was torture; I was barely able to complete it. I need to think carefully in future about post-long run recovery and refuelling. I was thinking of Sunday as a training run, but to put it in context, it was a bit stupid to run 12k two days after a half marathon!

    I reckon it isn't just about refuelling mid-run, although that is an issue, and without it you'd simply keel over. My observation is, though, for a lot of people it doesn't prevent a dodgy spell for a while. Refuelled, you can get through it. I think the body needs to be put through that regularly in training so it can become more efficient.

  • Interesting read. And whoever said that running was straight forward.. (although I guess the 90 min thing would apply to all / any exercise).

    Just read your bio (don't keep up to date on here as much as I used to / should) - very impressed with your achievements in that timescale - well done you!

    I'm still trucking along with my longest run being the good ole 10k.

    Someone once said to me that if I don't train to run further then I'll 'only ever be just 10k fit'. It's lived with me, since when has 10k been a "just" distance?!

    Anyways, well done you 😀🏃

  • Thanks for that. 10k is a respectable distance! If you're happy with that, then all power to your elbow. It's more than most people could imagine doing.

    I'm just enjoying learning more about what I can (and can't - had a horrible run today after Sunday's big one) do, and how the body works.

  • Silky Steve always told me that its after 90 minutes that we start to burn our fat stores, the body isnt used to it so protests!!! I definately start to feel it at 8 miles on every long run I have ever done and thats usually 90 minutes in... Well done on the 14 miles thats terrific...

  • Thanks, Ju. I'm harbouring the hope that given enough training (exposure to that 90 minute event) the body starts to get better at handling it. I shall try!

    14 miles (and the extra half) certainly felt good as a training run!

  • That's epic Steve! I wonder when you'll next be brave enough to try that again. The longest I've run is 1hr12min so no 90mins there, but I've experienced sudden feelings of needing sugar when doing long bike rides which were very hard to recover from - cycling is different though as it's easy to carry bananas etc, and also I never cycle competitively. But I'm wondering if it's more than just bad fuelling when that happens, perhaps the glycogen thing happens after 90mins of cycling too...

    Congrats on taking that 14.48 miler in your stride. I think a marathon would be an amazing next step - love how you keep pushing things further. I'm yet to repeat my 10k again, it will happen soon though :)

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