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Lose weight, save how much time in 5K
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I have seen various figures thrown around and while I know it varies from person to person, what on average would you say would be time saved in a 5K vs. lbs lost.
If I was to guess for myself, at 180 lbs or so, if I lost 10 pounds and still kept my strength and endurance, it would maybe equate to 45 seconds?????? this is a total guess. Thoughts? Studies would be great if you can show me a link to them.
Jeff
Just found this...not sure how legit it is.In terms of running, smaller is usually better. Packing extra body fat on your frame will slow you down. In his book, “Serious Runner’s Handbook”, running expert Tom Osler suggests that every pound of excess weight will decrease your running performance by 2 seconds per mile. So, if you add 10 pounds of unwanted body fat you will lose 20 seconds per mile from your running pace. There is little scientific evidence to back up that claim, but in both my personal and coaching experience I have found that number to be fairly accurate. Of course, that will vary from person to person, but there is no question that excess body fat weight will slow you down.
Last edited by: Jeff Spicoli: Oct 1, 12 10:32
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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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Jeff Spicoli wrote:
I have seen various figures thrown around and while I know it varies from person to person, what on average would you say would be time saved in a 5K vs. lbs lost.
If I was to guess for myself, at 180 lbs or so, if I lost 10 pounds and still kept my strength and endurance, it would maybe equate to 45 seconds?????? this is a total guess. Thoughts? Studies would be great if you can show me a link to them.
Jeff
Just found this...not sure how legit it is.In terms of running, smaller is usually better. Packing extra body fat on your frame will slow you down. In his book, “Serious Runner’s Handbook”, running expert Tom Osler suggests that every pound of excess weight will decrease your running performance by 2 seconds per mile. So, if you add 10 pounds of unwanted body fat you will lose 20 seconds per mile from your running pace. There is little scientific evidence to back up that claim, but in both my personal and coaching experience I have found that number to be fairly accurate. Of course, that will vary from person to person, but there is no question that excess body fat weight will slow you down.

Apocryphal lore is 2-5 seconds per lb lost per mile. Depends on some factors like efficiency, where you are on the whole scale of things, etc. 2 seconds is probably a good estimate, so for 10 lbs 45 seconds to a minute is probably a safe guess.

John



Top notch coaching: Francois and Accelerate3 | Follow on Twitter: LifetimeAthlete |
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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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In general of course, lighter is better for running. But that would be a nightmare of a thing to try and test reliably, with all the variables involved... weight vs pace (which pace, threshold? vo2max?). Also need to account for fitness, body fat % (weight doesnt necessarily mean good composition), recent nutrition (hydration & glycogen levels, caffeine etc), recent training (rest, taper), temperature & conditions on the day, etc.
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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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I have read for years about 2 seconds per mile pace per lb. I lost about 15 lbs, and was close to this. There is nothing negative about losing weight, unless one over does it.

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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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If you were to train more (say running) and lost 10 lbs through that, and say you trimmed 45 seconds per mile, there is no way to determine (outside of a controlled experiment) if the speed gain was from the 10 lbs lost, or the increase in running/training volume that lead to the weight loss. Maybe you just got faster because you ran a hell of a lot more. Or maybe it was from the decreased weight, or likely from both.

Anyway, I think it's pretty obvious someone not carrying extra weight will be faster (assuming they are fit). And I have also heard 2-5 seconds per mile per lb lost.

Good luck, I'm sure whatever the speed gain, you'll be faster with a little weight trimmed off. Report back after you've done it.

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Last edited by: Mendeldave: Oct 1, 12 11:08
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Re: Lose weight, save how much time in 5K [Mendeldave] [ In reply to ]
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Mendeldave wrote:
If you were to train more (say running) and lost 10 lbs through that, and say you trimmed 45 seconds per mile, there is no way to determine (outside of a controlled experiment) if the speed gain was from the 10 lbs lost, or the increase in running/training volume that lead to the weight loss. Maybe you just got faster because you ran a hell of a lot more. Or maybe it was from the decreased weight, or likely from both.

Anyway, I think it's pretty obvious someone not carrying extra weight will be faster (assuming they are fit). And I have also heard 2-5 seconds per mile per lb lost.

Good luck, I'm sure whatever the speed gain, you'll be faster with a little weight trimmed off. Report back after you've done it.

No, you probably can't differentiate between whether it's weight, efficiency, extra training, etc. But even if you don't understand the left side of the equation, the right side still comes out around 2-5 seconds/mile/lb from all the N=x that I've seen.

And I agree, it's most likely a multitude of different things adding up the create the increase.

John



Top notch coaching: Francois and Accelerate3 | Follow on Twitter: LifetimeAthlete |
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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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Went through this last year,

Started out at 185 lbs in early summer, got down to 151 by around christmas. This was kind of my "fat to fit" stage as I was out of the sport for 4 years.

5lbs = 30 seconds per 5km, for me - every ones different.

If you're really bored you can read about it on my blog (mo diet weeks 1-9)

Cheers,
Maurice
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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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I can give you the reverse. I'm as equally trained this year as last year but I'm about 10 lbs heavier. On the same courses I ran a 5K 40 seconds slower and half-marathon about 7 minutes slower.
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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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Here's my math:

Age 18, weight 145, 35-40 mpw (running only) 5k PR 16:15 (sea level)

Age 41, weight 180, 15 mpw runnning (cycling and strength training), 5k PR 20:55 (5500ft)

Lots of variables I know but the 2 seconds per lb, per mile is pretty close.

Formerly DrD
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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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I lost about 10lbs over the winter this year thinking I would get faster. I didn't.. I think I ended up losing too much strength in the process and didn't have enough energy. My bike times got worse as well..
Started focusing more on proper nutrition rather than weight.. put on a few more pounds and got faster. So I do think losing weight can have a negative impact

Team Every Man Jack
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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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Jack Daniels says 1-2sec per pound

Eric - "Train Smart, Race Smart, Finish Strong"
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Re: Lose weight, save how much time in 5K [ejchet] [ In reply to ]
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ejchet wrote:
Jack Daniels says 1-2sec per pound

Jack talks to me sometimes too.....oh, I think we are talking about different jacks here


Tim


Tim
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Re: Lose weight, save how much time in 5K [rj_tri] [ In reply to ]
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rj_tri wrote:
I lost about 10lbs over the winter this year thinking I would get faster. I didn't.. I think I ended up losing too much strength in the process and didn't have enough energy. My bike times got worse as well..
Started focusing more on proper nutrition rather than weight.. put on a few more pounds and got faster. So I do think losing weight can have a negative impact

You make a good point. Proper nutrition during weight loss is key. If you lose weight by simply running a calorie deficit, you run the risk of cannibalizing your muscle instead of fat (by not taking in the right nutrition AT THE RIGHT TIME ie protein during a long workout and after a hard workout).

I've done this before - I lost 10 lbs over the winter and despite a hard winter cycling schedule I lost 10+% off my bike FTP. The problem was that I was so worried about the calories that I didnt eat after working out. Big mistake.
However, you can still run a calorie deficit and continue to improve fitness and performance. More recently, I am down another 10 lbs and done so with running a calorie deficit. However, after a workout I take in a lot of protein right afterward. My run times are improving, but as a measurable benchmark, by bike power numbers across the spectrum are up about 5% over 4 months.

Here's a reasonably good article on guidelines for what you should eat and when:
http://www.bikeradar.com/...eed-and-power-24762/

Bottom line, if you do it right, you'll get faster while you lose weight

- Pete


Luckily my over eating disorder is offset by my over exercising disorder
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Re: Lose weight, save how much time in 5K [rj_tri] [ In reply to ]
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rj_tri wrote:
I lost about 10lbs over the winter this year thinking I would get faster. I didn't.. I think I ended up losing too much strength in the process and didn't have enough energy. My bike times got worse as well..
Started focusing more on proper nutrition rather than weight.. put on a few more pounds and got faster. So I do think losing weight can have a negative impact

Oh, absolutely true. Periodic testing should be part of the arsenal of every athlete, so you can detect/avoid the downside.

John



Top notch coaching: Francois and Accelerate3 | Follow on Twitter: LifetimeAthlete |
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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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Too may variables with losing the 10 lbs... and why struggle? Take 2 ounces off each foot (maybe a useless toe) and be 15 seconds faster per mile overnight!
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Re: Lose weight, save how much time in 5K [ejchet] [ In reply to ]
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For me this is the closest estimate to what I find.

Since I did my Ironman I've put on 7lbs and have found that I run my favourite 10 mile tempo run Approx 15 seconds per mile slower (7min/mile) at the same HR than I did pre Iron man (6:45min/mile). Obviously there are a number of variables at play but if you work off 2-3sec/mile per lbs I doubt you'll be far off.
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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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I think if you wentnon one of those designer diets for a few months you would be really fast. Say............ A gluten free diet :0)

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Re: Lose weight, save how much time in 5K [Pedalhead] [ In reply to ]
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Pedalhead wrote:
Too may variables with losing the 10 lbs... and why struggle? Take 2 ounces off each foot (maybe a useless toe) and be 15 seconds faster per mile overnight!

I've seen the light shoe thing being thrown around a bunch and don't buy it for a second (excuse the pun). Sure, a set of 12 ounce trainers will be different than some 7 ounce flats, but within reason.. I don't believe it. 9ounce vs. 7 ounce shoe, no way there's a 15sec/mile difference. Or even a 5sec/mile difference.
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Re: Lose weight, save how much time in 5K [phoenixR34] [ In reply to ]
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Hmmm, I wonder why middle-distance runners wear very light flats or spikes? Research on shoe weight and the energy cost of running provides indisputable evidence of the higher efficiency of running with light shoes. Over the marathon distance, a 2oz lighter shoe equates to the energy cost for running one mile. That saving of energy should translate into a faster time.

phoenixR34 wrote:
I've seen the light shoe thing being thrown around a bunch and don't buy it for a second (excuse the pun). Sure, a set of 12 ounce trainers will be different than some 7 ounce flats, but within reason.. I don't believe it. 9ounce vs. 7 ounce shoe, no way there's a 15sec/mile difference. Or even a 5sec/mile difference.
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Re: Lose weight, save how much time in 5K [Pedalhead] [ In reply to ]
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Pedalhead wrote:
Hmmm, I wonder why middle-distance runners wear very light flats or spikes? Research on shoe weight and the energy cost of running provides indisputable evidence of the higher efficiency of running with light shoes. Over the marathon distance, a 2oz lighter shoe equates to the energy cost for running one mile. That saving of energy should translate into a faster time.

Yeah, same reason triathletes use aero water bottles.
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Re: Lose weight, save how much time in 5K [Pedalhead] [ In reply to ]
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There is a big difference between racing flats and trainers. I run in a trainer that is about 8 ounces and in a racer that is about 5 ounces. I run about 5 -10 sec per kilometer faster in my racers. However this may be a placebo effect.

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Re: Lose weight, save how much time in 5K [Jeff Spicoli] [ In reply to ]
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Jeff Spicoli wrote:
If I was to guess for myself, at 180 lbs or so, if I lost 10 pounds and still kept my strength and endurance, it would maybe equate to 45 seconds?????? this is a total guess.


How about: go run a mile at 5K pace. The next day (or when recovered) put on a 10 pound weight belt and run the same mile at the same effort and HR. Subtract 3.1 times the difference. Should be in the ballpark; better than a total guess, anyway....
Last edited by: dano-oly: Oct 2, 12 17:42
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Re: Lose weight, save how much time in 5K [Pedalhead] [ In reply to ]
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Brilliant
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Re: Lose weight, save how much time in 5K [ejchet] [ In reply to ]
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It is possible to calculate an estimate.

Your fitness level can be estimated by a cooper test.
The number you get has the value (mmol O2 )/ kg

180 lbs ~ 90 kg.
You run 3000 m on a cooper ~approx fitness level is 54 (mmol O2) / kg.

Now you loose 10 Lbs (5 kg), we assume no difference in the oxygen uptake.
Thus your fitness level will go from 54 to 56 (54*90/85).
It will give you a distance of 3150 m on 12 min.

Difference in speed is going from 4:10 min/km to 3:50 min/km or roughly
4 sek/km pr. kg.

I have seen litterature suggest 2-3 sek/km pr. kg.
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Re: Lose weight, save how much time in 5K [GoJohnnyGo] [ In reply to ]
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GoJohnnyGo wrote:
Brilliant


8+ years later I wonder what PedalHead things about carbon shoes.
Last edited by: Ironnerd: Apr 8, 22 15:32
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