Influence of weight (or fat%) on running speed

JasperTheStudent
JasperTheStudent Posts: 20
in Fitness and Exercise
Hi,

I was wondering, how does weight influemce running speed? If you go from 100 to 90 kg (and let's assume all that loss is fat), does your running speed go up by 10%?

My hypothesis is that it should go up more, like 15%.

I started running when I was 96 kg and now I am 88. My 10 km race speed was 9-10 km/h and now it's 14-15 km/h, so the increase is huge for the amount I lost. But weight loss is far from the only factor involved; I quit smoking and I trained a lot, so my endurance is much better now.

But I plan to lose another 6 kg and I wonder what it will bring me :)

Any ideas?

Replies

  • Zomoniac
    Zomoniac Posts: 1,169 Member
    I'd think the effect was entirely negligible, especially over those distances. Over the last few years my weight has been everything from 73kg up to 103kg, and my 10k time has been between 42 and 65 minutes, and there's been next to no correlation with weight, and everything to do with how I'm feeling and how well I'm trained at the time. My standard pace was 4km/h quicker when I was 85kg than it was this morning at 76kg because I was better trained for it.

    Which isn't to say that trying to lug 150k round a marathon course won't be debilitating, but if you lose another 6kg and your pace continues to skyrocket then I doubt that will be why.
  • jo_marnes
    jo_marnes Posts: 1,601 Member
    It won't affect your speed. Your fitness and your training will affect your speed. Weight loss will often include muscle loss.... so its negligible. If you want to increase speed, add interval training, set goals and stick at it
  • melaniecheeks
    melaniecheeks Posts: 6,349 Member
    There is an effect (in fact I read an article about this recently, I'll see if I can link to it) - but it isn't as neat and straightforward as your suggestion.
  • melaniecheeks
    melaniecheeks Posts: 6,349 Member
    http://www.runnersworld.com/weight-loss/whats-your-ideal-weight
  • Lisah8969
    Lisah8969 Posts: 1,247 Member
    I have a table taped to my fridge that I got from runner's world. It says how much faster you get with weight loss.

    http://www.myfitnesspal.com/post/new/1196693-influence-of-weight-or-fat-on-running-speed

    I have done 7 Half Marathons and the first one I did being down 60 pounds was around 25 minutes better than my previous PR so pretty much right on target with what they said. I trained like crazy when I was heavier and trained like crazy when I was lighter. Still 30 pounds to go so I look forward to knocking another 13 minutes off my best.
  • SingingSingleTracker
    SingingSingleTracker Posts: 1,866 Member
    Hi,

    I was wondering, how does weight influemce running speed? If you go from 100 to 90 kg (and let's assume all that loss is fat), does your running speed go up by 10%?

    My hypothesis is that it should go up more, like 15%.

    I started running when I was 96 kg and now I am 88. My 10 km race speed was 9-10 km/h and now it's 14-15 km/h, so the increase is huge for the amount I lost. But weight loss is far from the only factor involved; I quit smoking and I trained a lot, so my endurance is much better now.

    But I plan to lose another 6 kg and I wonder what it will bring me :)

    Any ideas?

    Power to Weight Ratio or also known as Strength to Weight Ratio

    http://triathlons.thefuntimesguide.com/2009/01/power_weight_ratio.php

    3 Power-to-Weight Ratio

    Pro triathletes typically have body fat percentages in the region of 5-10% (men) and 10-15% (women). A moderately trained age-group triathlete will be in the region of 12-17% (men) and 20-25% (women). When you then consider that 1kg of reduced body weight can result in around 2-3 seconds saving per kilometre, we can work out that losing a few kilos of excess body fat will transform our 10km running performance. Play around with the numbers for yourself and you will see what I mean. Your 10k PB is literally a few less high-calorie snacks away. The Brownlees and Helen Jenkins look that slim for a reason – if you want more running speed, quit the cakes!

    Read more: Triathlon Running: Three Secrets To Run Faster | TriRadar.com http://www.triradar.com/training-advice/three-secrets-to-running-faster/#ixzz2seGLkN8B
  • 3rdwoozie5
    3rdwoozie5 Posts: 46 Member
    there is an ole saying in ski jumping. Which can be applied to just about any sport. "Fat doesn't Fly".
  • SingingSingleTracker
    SingingSingleTracker Posts: 1,866 Member
    there is an ole saying in ski jumping. Which can be applied to just about any sport. "Fat doesn't Fly".

    LOL. Luckily, running helps the fat fly off.... ;-)

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