How much running improvement comes from weight loss alone?

Dec 17, 08 14:27

Post #1 of 138 (9947 views)

I have been at the US T&F and CC coaches assn meeting and one of the booths next to me had an "unweighting machine" associated with a treadmill. (If you want one the cost was $75K.) It was capable of unweighting in small increments up to 80% unweighting, without restricting running form.

Anyhow, I got to thinking about their device and came to ask them the question as to how much oxygen consumption went down as unweighting went up. They did not have specific data but were able to say that when they unweighted to 85% this would reduce their HR about 10 beats (150 to 140) for the same treadmill speed.

This suggests to me that a 15% reduction in weight results in an approximate 7.5% increase in running efficiency.

Do you think this would translate to a 7.5% increase in speed?

Do you think this would be a good rule of thumb, that a 10% reduction in weight should result in a 5% improvement in speed?

Would you say that anything more than this would have to come from training effect?

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: How much running improvement comes from weight loss alone? [Frank Day] [ In reply to ]

Dec 17, 08 14:41

Post #2 of 138 (9921 views)

In Reply To:

This suggests to me that a 15% reduction in weight results in an approximate 7.5% increase in running efficiency.

How do you figure that?

Erik
Strava

Re: How much running improvement comes from weight loss alone? [Frank Day] [ In reply to ]

Dec 17, 08 14:51

Post #3 of 138 (9887 views)

Personal experience over the past 5 years has shown me that every 10 pounds of "extra" weight (overweight fat or upper body muscle) gives an automatic 1 minute per mile increase in speed at the same effort and training load. And I have gone up and down this scale multiple times over that time period.

Me at 200 lbs = 9:30 easy and 8:15 5K pace

Me at 190 lbs = 8:30 easy and 7:30 5K pace

Me at 180 lbs = 7:30 easy and 6:30 5K pace

Me at 172 lbs = 7:00 easy and 5:45 5K pace

The latter is my fastest, healthy, most disciplined weight to maintain.

Re: How much running improvement comes from weight loss alone? [markvoss] [ In reply to ]

Dec 17, 08 14:54

Post #4 of 138 (9877 views)

And, other than semi-hourly references ;-) to them in this forum, I've never even seen Power Cranks.

Re: How much running improvement comes from weight loss alone? [markvoss] [ In reply to ]

Dec 17, 08 14:58

Post #5 of 138 (9858 views)

Yes but what are you doing to lose the weight? If you lost 10 pounds by running more or at a higher intensity than that could have at least as much an affect on your pace improvements than just the fact that you lost 10 pounds.

Re: How much running improvement comes from weight loss alone? [mcdoublee] [ In reply to ]

Dec 17, 08 15:01

Post #6 of 138 (9852 views)

In Reply To:

In Reply To:

This suggests to me that a 15% reduction in weight results in an approximate 7.5% increase in running efficiency.

How do you figure that?

HR correlates pretty well with oxygen consumption. If speed remains the same and oxygen consumption drops, efficiency improves.

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: How much running improvement comes from weight loss alone? [mcdoublee] [ In reply to ]

Dec 17, 08 15:03

Post #7 of 138 (9845 views)

In Reply To:

In Reply To:

This suggests to me that a 15% reduction in weight results in an approximate 7.5% increase in running efficiency.

How do you figure that?

HR correlates pretty well with oxygen consumption. If speed remains the same and oxygen consumption drops, efficiency improves.

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: How much running improvement comes from weight loss alone? [Frank Day] [ In reply to ]

Dec 17, 08 15:07

Post #8 of 138 (9834 views)

In Reply To:

In Reply To:

In Reply To:

This suggests to me that a 15% reduction in weight results in an approximate 7.5% increase in running efficiency.

How do you figure that?

HR correlates pretty well with oxygen consumption. If speed remains the same and oxygen consumption drops, efficiency improves.

Uh, No.

When the machine reduces the runners weight by 15%, they do less work, hence lower oxygen consumption and lower heart rate.

You should not draw conclusions about efficiency without data that actually measures efficiency...

Erik
Strava

Re: How much running improvement comes from weight loss alone? [mcdoublee] [ In reply to ]

Dec 17, 08 15:21

Post #9 of 138 (9808 views)

In Reply To:

In Reply To:

In Reply To:

In Reply To:

This suggests to me that a 15% reduction in weight results in an approximate 7.5% increase in running efficiency.

How do you figure that?

HR correlates pretty well with oxygen consumption. If speed remains the same and oxygen consumption drops, efficiency improves.

Uh, No.

When the machine reduces the runners weight by 15%, they do less work, hence lower oxygen consumption and lower heart rate.

You should not draw conclusions about efficiency without data that actually measures efficiency...

Huh? Perhaps we are defining running efficiency differently. If I can run just as fast while burning less oxygen then I would consider myself more efficient. What would you call it?

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: How much running improvement comes from weight loss alone? [markvoss] [ In reply to ]

Dec 17, 08 15:24

Post #10 of 138 (9799 views)

In Reply To:

Personal experience over the past 5 years has shown me that every 10 pounds of "extra" weight (overweight fat or upper body muscle) gives an automatic 1 minute per mile increase in speed at the same effort and training load. And I have gone up and down this scale multiple times over that time period.

Me at 200 lbs = 9:30 easy and 8:15 5K pace

Me at 190 lbs = 8:30 easy and 7:30 5K pace

Me at 180 lbs = 7:30 easy and 6:30 5K pace

Me at 172 lbs = 7:00 easy and 5:45 5K pace

The latter is my fastest, healthy, most disciplined weight to maintain.

My question goes to the effect of weight alone. Your data has 5 years of running base that is complicating the analysis. I suspect you would be seeing speed improvements over this time even if your weight had been constant. It is not possible to know how much of your improvement is due to weight loss and the 5 years of additional running you did during this period.

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: How much running improvement comes from weight loss alone? [markvoss] [ In reply to ]

Dec 17, 08 15:25

Post #11 of 138 (9794 views)

In Reply To:

Personal experience over the past 5 years has shown me that every 10 pounds of "extra" weight (overweight fat or upper body muscle) gives an automatic 1 minute per mile increase in speed at the same effort and training load. And I have gone up and down this scale multiple times over that time period.

Me at 200 lbs = 9:30 easy and 8:15 5K pace

Me at 190 lbs = 8:30 easy and 7:30 5K pace

Me at 180 lbs = 7:30 easy and 6:30 5K pace

Me at 172 lbs = 7:00 easy and 5:45 5K pace

The latter is my fastest, healthy, most disciplined weight to maintain.

STOP That nonsense!

Don't you know the 'ST Experts' all say that extra weight doesn't make you slower. You will just encourage the clydes to have excuses

Re: How much running improvement comes from weight loss alone? [Frank Day] [ In reply to ]

Dec 17, 08 15:37

Post #12 of 138 (9773 views)

In Reply To:

In Reply To:

In Reply To:

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This suggests to me that a 15% reduction in weight results in an approximate 7.5% increase in running efficiency.

How do you figure that?

HR correlates pretty well with oxygen consumption. If speed remains the same and oxygen consumption drops, efficiency improves.

Uh, No.

When the machine reduces the runners weight by 15%, they do less work, hence lower oxygen consumption and lower heart rate.

You should not draw conclusions about efficiency without data that actually measures efficiency...

Huh? Perhaps we are defining running efficiency differently. If I can run just as fast while burning less oxygen then I would consider myself more efficient. What would you call it?

I don't think this is the first time you have been confused by the word efficiency.

Efficiency = (energy out) / (energy in)

You can use HR as a proxy for oxygen consumption which will tell you energy in. Energy out is calculated from speed and weight. That $75k treadmill effectively reduces your weight; MEANING, it requires less energy for you to run the same speed.

Also, somewhat related, they don't give world records to people running on moving sidewalks. Why do you think that is?

Erik
Strava

Last edited by: mcdoublee: Dec 17, 08 16:31

Re: How much running improvement comes from weight loss alone? [Frank Day] [ In reply to ]

Dec 17, 08 15:38

Post #13 of 138 (9769 views)

Hey Frank:

So be scientific (and I'd be willing to volunteer as a victim...I mean a participant). You lead a study! Set up a study of approximately 10 to 15 men and 10 to 15 women that can stand to loose 10 lbs. Establish a criteria for measuring current speed. Provide the individuals with a protocal to loose 10 lbs that can be duplicated by all 20 to 30 participants. After loosing the 10 lbs., re-test for the determined criteria for measuring speed to determine the improvement.

Re: How much running improvement comes from weight loss alone? [Frank Day] [ In reply to ]

Dec 17, 08 15:43

Post #14 of 138 (9749 views)

In Reply To:

In Reply To:

Personal experience over the past 5 years has shown me that every 10 pounds of "extra" weight (overweight fat or upper body muscle) gives an automatic 1 minute per mile increase in speed at the same effort and training load. And I have gone up and down this scale multiple times over that time period.

Me at 200 lbs = 9:30 easy and 8:15 5K pace

Me at 190 lbs = 8:30 easy and 7:30 5K pace

Me at 180 lbs = 7:30 easy and 6:30 5K pace

Me at 172 lbs = 7:00 easy and 5:45 5K pace

The latter is my fastest, healthy, most disciplined weight to maintain.

My question goes to the effect of weight alone. Your data has 5 years of running base that is complicating the analysis. I suspect you would be seeing speed improvements over this time even if your weight had been constant. It is not possible to know how much of your improvement is due to weight loss and the 5 years of additional running you did during this period.

Ok how about this place top 10 in races with 700 - 1000 racers. 5 years later gain 40lbs just about all muscle BUT still doing tri training(so the run base is getting bigger) and am lucky to place in top 30% and run times in Olympic are 15 minutes slower.

Re: How much running improvement comes from weight loss alone? [Cyclingmaniac] [ In reply to ]

Dec 17, 08 15:47

Post #15 of 138 (9740 views)

In Reply To:

Hey Frank:

So be scientific (and I'd be willing to volunteer as a victim...I mean a participant). You lead a study! Set up a study of approximately 10 to 15 men and 10 to 15 women that can stand to loose 10 lbs. Establish a criteria for measuring current speed. Provide the individuals with a protocal to loose 10 lbs that can be duplicated by all 20 to 30 participants. After loosing the 10 lbs., re-test for the determined criteria for measuring speed to determine the improvement.

Still wouldn't be sure to show what is happening as they would still be running so run base is bigger than the year before.

Re: How much running improvement comes from weight loss alone? [mcdoublee] [ In reply to ]

Dec 17, 08 15:57

Post #16 of 138 (9718 views)

In Reply To:

In Reply To:

In Reply To:

In Reply To:

In Reply To:

In Reply To:

This suggests to me that a 15% reduction in weight results in an approximate 7.5% increase in running efficiency.

How do you figure that?

HR correlates pretty well with oxygen consumption. If speed remains the same and oxygen consumption drops, efficiency improves.

Uh, No.

When the machine reduces the runners weight by 15%, they do less work, hence lower oxygen consumption and lower heart rate.

You should not draw conclusions about efficiency without data that actually measures efficiency...

Huh? Perhaps we are defining running efficiency differently. If I can run just as fast while burning less oxygen then I would consider myself more efficient. What would you call it?

I don't think this is the first time you have been confused by the word efficiency.

Efficiency = (energy in) / (energy out)

You can use HR as a proxy for oxygen consumption which will tell you energy in. Energy out is calculated from speed and weight. That $75k treadmill effectively reduces your weight; MEANING, it requires less energy for you to run the same speed.

Also, somewhat related, they don't give world records to people running on moving sidewalks. Why do you think that is?

How do you calculate "energy out" in a runner? All we have here is energy consumed and speed. I know of no way to calculate work performed by the runner, do you?

If we were to take a car and take 500 lbs out of the trunk and then find out that it takes less gas to go 50 mph than before we say the car has better fuel efficiency even though we don't know exactly how much energy has changed. The engine of the car has not changed but it is now more fuel efficient because of the weight change. If we look at the runner from the point of view of the cardiovascular system (the heart), the capability of the heart has not changed with the weight loss but it now requires less energy to propel the body the same speed. The runner, as is the car, is now more efficient.

So, you don't like the term "efficiency" to describe this change. What word would you use?

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Last edited by: Frank Day: Dec 17, 08 15:59

Re: How much running improvement comes from weight loss alone? [markvoss] [ In reply to ]

Dec 17, 08 16:05

Post #17 of 138 (9704 views)

dude I an 5'9" and 168 pnds 39 yearsd old wish I could go 5:45 minute miles for 3.1 miles. Currently best pae has been around 6:45 minutes for 3.1 miles. How many miles a week do you put in to get that time and what is your Average HR after runnung it if you know? Why I want to know is thats kind of my target time for sometime late spring.

__________________________________________________
Official Polar Ambassador
http://www.google.com/...P7RiWyEVwpunlsc2JtQQ

Re: How much running improvement comes from weight loss alone? [RBR] [ In reply to ]

Dec 17, 08 16:20

Post #18 of 138 (9670 views)

In Reply To:

In Reply To:

Hey Frank:

So be scientific (and I'd be willing to volunteer as a victim...I mean a participant). You lead a study! Set up a study of approximately 10 to 15 men and 10 to 15 women that can stand to loose 10 lbs. Establish a criteria for measuring current speed. Provide the individuals with a protocal to loose 10 lbs that can be duplicated by all 20 to 30 participants. After loosing the 10 lbs., re-test for the determined criteria for measuring speed to determine the improvement.

Still wouldn't be sure to show what is happening as they would still be running so run base is bigger than the year before.

Maybe this is a dumb idea, but what about ADDING weight to runners, so that you could keep all of the other variables constant? (Sorta like some of the running commuters on the 100/100 thread have described.)

-----
Over 4.5 years bike crash free.

Re: How much running improvement comes from weight loss alone? [bmanners] [ In reply to ]

Dec 17, 08 16:20

Post #19 of 138 (9668 views)

well... i'm 32 and 6'2" and 195 and can also put down a 6:45 paced 5k. I would hope that I will increase my speed if I get down 10lbs.

--
MyGearGarage - Track all your gear!

Re: How much running improvement comes from weight loss alone? [Frank Day] [ In reply to ]

Dec 17, 08 16:49

Post #20 of 138 (9621 views)

In Reply To:

In Reply To:

In Reply To:

In Reply To:

In Reply To:

In Reply To:

In Reply To:

This suggests to me that a 15% reduction in weight results in an approximate 7.5% increase in running efficiency.

How do you figure that?

HR correlates pretty well with oxygen consumption. If speed remains the same and oxygen consumption drops, efficiency improves.

Uh, No.

When the machine reduces the runners weight by 15%, they do less work, hence lower oxygen consumption and lower heart rate.

You should not draw conclusions about efficiency without data that actually measures efficiency...

Huh? Perhaps we are defining running efficiency differently. If I can run just as fast while burning less oxygen then I would consider myself more efficient. What would you call it?

I don't think this is the first time you have been confused by the word efficiency.

Efficiency = (energy out) / (energy in)

You can use HR as a proxy for oxygen consumption which will tell you energy in. Energy out is calculated from speed and weight. That $75k treadmill effectively reduces your weight; MEANING, it requires less energy for you to run the same speed.

Also, somewhat related, they don't give world records to people running on moving sidewalks. Why do you think that is?

How do you calculate "energy out" in a runner? All we have here is energy consumed and speed. I know of no way to calculate work performed by the runner, do you?

With physics. The specifics of which, I can't tell you.

Perhaps someone can chime in to explain how to calculate the work or power required to run a given speed. I do not know the answer but also do not think it's too difficult of a problem to get a reasonably close estimate. It is certainly a function of speed and weight. If either increases, the energy required to sustain the speed will increase. If either decrease the amount of energy required will also decrease. Do we at least agree on that?

The truck in your example just unnecessarily complicates matters. Let's just say that it is doing less work and that is why it uses less gas.

I will now go run for a little under 8 miles while attempting to keep my heart rate at precisely 160. When I'm going up hill my speed will decrease, when I go downhill my speed will increase. Will this work? Why? Will my efficiency change as I'm running?

Finally, I edited my last post to correct a typo in the efficiency equation.

Erik
Strava

Re: How much running improvement comes from weight loss alone? [RBR] [ In reply to ]

Dec 17, 08 16:50

Post #21 of 138 (9619 views)

In Reply To

Personal experience over the past 5 years has shown me that every 10 pounds of "extra" weight (overweight fat or upper body muscle) gives an automatic 1 minute per mile increase in speed at the same effort and training load. And I have gone up and down this scale multiple times over that time period.

Me at 200 lbs = 9:30 easy and 8:15 5K pace

Me at 190 lbs = 8:30 easy and 7:30 5K pace

Me at 180 lbs = 7:30 easy and 6:30 5K pace

Me at 172 lbs = 7:00 easy and 5:45 5K pace

The latter is my fastest, healthy, most disciplined weight to maintain.[/reply]
STOP That nonsense!

Don't you know the 'ST Experts' all say that extra weight doesn't make you slower. You will just encourage the clydes to have excuses[/reply]
Actually this will encourage clydes like me who are only a little slower than you to lose that last 20 pounds or so, and then we'll be faster than you.

Live long and surf!

Re: How much running improvement comes from weight loss alone? [Frank Day] [ In reply to ]

Dec 17, 08 16:58

Post #22 of 138 (9599 views)

1 lost pound = 2 seconds/mile. That is a nice rule of thumb that people toss around. I am sure its not accurate or ever been tested, but that is what my simple mind uses.

Re: How much running improvement comes from weight loss alone? [mrtrik] [ In reply to ]

Dec 17, 08 16:59

Post #23 of 138 (9596 views)

In Reply To:

well... i'm 32 and 6'2" and 195 and can also put down a 6:45 paced 5k. I would hope that I will increase my speed if I get down 10lbs.

Some research has shown that you could expect a 20 second per mile improvement from your 10 pound weight loss.

Re: How much running improvement comes from weight loss alone? [Frank Day] [ In reply to ]

borgerendurance

Dec 17, 08 17:17

Post #24 of 138 (9567 views)

At 167 lbs ran slowww... 28:47 8k XC, ave. 50-65 miles/week, next year
at 152 lbs ran 26:31 same mileage feeling much better/easier. No other changes between cross country seasons other than weight loss (due to working in Missouri for a month coaching sports and sweating 24/7, came back was feeling great running, hopped on the scale and wow! I was skinny. So I cut down my bad eating habits and stayed at that weight that season. Now my question is, as a triathlete what weight is most efficient. I know for the run, but the thinness could hurt my swim. If it helps on bike and run, hurts on the swim (swim being least important in my mind for non-drafting events) I'm leaning towards lighter is better.

Ryan Borger - Denver, CO: Realtor. Former pro triathlete/coach. Cancer survivor. podiumproperties.com

Re: How much running improvement comes from weight loss alone? [rundutch22] [ In reply to ]

Dec 17, 08 17:24

Post #25 of 138 (9551 views)

Could this at all be related to BMI? I think this is a more accurate measurement for different people. Mine's 20. Is that bad? I want to lose like 7 pounds in the New Year.

________________________________________________________________________________
The only one who can tell you "you can't" is you. And you don't have to listen. --Nike

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