Sunday, October 10, 2010

A measurement of fitness

In spite of not racing a half marathon in Melbourne today (or perhaps because of that fact), I'm feeling pretty good. Quite a few of my mates were running — you can check out their results in due course at Speedygeoff's. I ran 44 kilometres this past week, including a session of 200 metre repeats on the lush grass track at Calwell. As expected, these 200s were a bit of an eye-opener. They averaged 48.5 seconds (4:02 kilo pace), so pretty slow. The only other time I've run 200s this year was back in June and those averaged 45.3 seconds. I need to do more of this type of running.

Being a bit of a pedantic bastard, I've made a habit (regularly since 2006 and haphazardly before then) of recording my average heart-rate on regular (non-track-session) runs. I record my "average heart-beats per kilometre", for I believe this is a good measurement of aerobic fitness. I call this the "RS" number (for marathoner Robert Song who gave me the idea). On the 3rd of October I ran 10k at 866 heart-beats per km. Yesterday I ran the same course at 833 heart-beats per km, so that indicates a fitness improvement in one week. It's exciting how fast one improves after a lay-off! The faster one runs the more efficient one is, so running speed needs to be not too much at variance when using this test (and that goes for weather conditions too).

One thing I haven't done well in recent years is to match leg strength and speed to improving aerobic fitness. Having a comfortably low heart-rate is great, but it's even better to also have speed and strength in the legs. Short intervals, short hill repeats, and running drills are regular sessions I plan on doing to address this shortcoming. I hope all who raced on the weekend enjoyed it and ran well. I'll catch up with your blogs over the next day or two.

DateTimeAve HRH-beats/kmDescription
31 Oct 199341:2016467810k race
10 Nov 199374:52148652Corkwoods 17k
16 Nov 200758:53124730Pines 10k
7 Aug 200959:29120714Pines 10k
3 Oct 201060:34143866School 10k
9 Oct 201058:39142833School 10k

The above table shows that I'm "fit" when heart-beats per kilometre are 730 or better


Blogger plu said...


It is interesting when you have some data to make the comparisons. Good aerobic fitness to carry forward.


9:31 pm  
Blogger Grellan said...

I like it. Must try it myself. Good to see the improvement.

4:16 am  
Blogger Girl In Motion said...

Ya big geek! :-) Cool way of thinking, never heard of that before, but most importantly, yay on the improvements!

1:52 pm  
Blogger nev said...

Interesting concept. Assuming that your maximum HR decreases as we age, then if you maintain and use a constant HR to measure fitness, then you must be putting in more "effort" for that same level of fitness? Good luck with your training and the coming track season.

6:12 pm  
Blogger jojo said...

my HR are someties scary in races(and training!) shorter stuff though i spose...
but they were the hAy days i spose- you know, when i USED to run!!!!

10:37 pm  
Blogger Scott Brown said...

How do you record average heart-beats per kilometre, Ewen? Cause when I tried it my hand kept slipping off my wrist and even when I could manage to keep a grip I tended to lose count around 500 beats and have to start over again ;)

Or are you taking your pulse on your neck when you do this and screaming out loud every 50 digits so you don't lose count?

12:10 am  
Blogger Ewen said...

Thanks Plu. I'm glad I kept all those old diaries. All the best for Nepean, and those M50 PBs.

Grellan, thanks. It's a gradual improvement, but measurable.

Flo, I fear I might have been even geekier had there been computers around when I was at school ;)

Nev, my max HR has declined. In '93 it was about 182, now it's about 166-7. That means racing HR and all other HRs are lower, but the effort (% of max) feels the same as before. I'm running slower, but I suspect a good bit of that is due to a shorter stride from not doing as much speedwork as I did in the old days.

Jojo, I remember when you used to run 2:30ish 800s, and it wasn't that long ago - this year! You'll be back better than ever this time next year.

That's good Scott. Yes, I get my backwards-leaning style from taking my pulse on my neck as I'm running. I'm good at maths, so I count by tens, then multiply the average per minute by the average pace per km ;)

8:39 pm  
Blogger Sling Runner said...

Interesting stats. But I think the 1993 10k time is surely a typo!

12:18 am  
Blogger Ewen said...

Sling, no, that's correct. It wasn't my best race in '93. There was a strong head-wind for the first half. Earlier in the year I ran 5k in 17:59, then towards the end of the year 4:49.1 for 1500m.

8:55 pm  
Blogger Luckylegs said...

Wow! You used be very fast back in '93!

12:51 pm  
Blogger Love2Run said...

I like this new stat but just have to figure out how to figure it out!! Now they tell me I'm a biologist so it shouldn't be to difficult... Nice to see you on the up and up!

4:48 am  
Blogger Ewen said...

Thanks Luckylegs. I didn't think I was fast at the time, but it was fun racing in the first 10% of the field.

Mike, you're almost as funny as Scott Brown. You need to be a mathematician to figure it out ;) One useful thing about this stat (heart-beats per km), is that you can see that your fitness has improved on a run, even though the time for the run is slower than usual.

7:33 pm  
Blogger RICK'S RUNNING said...

How much has your max pulse dropped over the years?
Back when I was 28 i could hit 185 BPM, now I'm lucky to hit 160 BPM.
I think my heart has got bigger over the years and so maybe does not need to beat as fast to supply the same amout of blood round the body!
glad to hear your feeling better, now you have your medical condition sorted you should start to fly >>>>

5:59 am  
Blogger RICK'S RUNNING said...

P.S. back in 1999 I averaged 160 bpm in the London marathon to run 2.49
this year I averaged around 130bpm to run 2.47 at London!!!

6:02 am  
Blogger Ewen said...

Hi Rick. My maximum has come down by roughly 1 beat per year. When I was 30 it was about 185. A few weeks back I recorded 164 by sprinting the last 100m of the last interval of a session, so I guess my maximum is no more than a few beats higher than that.

I think you're right about how the heart can become more efficient (and have a bigger stroke volume) with the right training. Very fit runners aren't limited in their speed by the heart-rate. It's usually at the muscular level. I read somewhere about Viren racing at a HR of around 130 which would have been a very low % of his maximum. Your London HR is about 515 beats per km, so you were very fit when you ran 2:47!

7:38 pm  
Anonymous Anonymous said...

It is great that you are recovering your fitness.

With regard to the decrease in beats per Km as running speed increases, I do not think that it is because running efficiency increases with increased pace – in fact energy consumed per Km remains almost constant as pace increases. However energy consumption per minute increases and the heart beats more forcefully, so fewer heart beats are required to deliver a given amount of blood (and oxygen). Whatever the explanation, I agree that beats per Km is a useful estimate of fitness provided it is assessed at approximately the same speed on each occasion.

7:50 am  
Blogger Ewen said...

Thanks for that explanation Canute. That supports my own experience. When walking for instance (where the heart is not beating forcefully), I'd have a beats per Km of 900 or so.

9:18 pm  

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