Six feet, 150 pounds. Personal best for 3k is 8:30. Now, let's say I drop 10 pounds by next winter. Aside from the gains in fitness from training, let's assume that my fitness remains idle, but I drop 10 pounds. From what I have read and heard over the years, is that the cost per pound of fat per mile is 2 seconds. 10lbs x 2s = 20 seconds per mile. Over 3k, would this indicate a 38 second improvement over 3k with weight reduction alone?
The rule of thumb is that each pound of "extra" body weight over your ideal number adds 70 seconds/mile.
70 seconds!? From a coaching perspective I've seen guys and girls drop tremendous amounts of weight looking border line anorexic but still managed to perform extremely well. I believe there is some truth to the lighter you are the faster you are. But there has to be a line when too light undermines performance. I don't know where that line is though.
554 wrote:
The rule of thumb is that each pound of "extra" body weight over your ideal number adds 70 seconds/mile.
12:37 here I come!
12:37 for what distance?
554 wrote:
12:37 for what distance?
Obviously the 5k because that is the world record.
the general rule is 3 - 5 seconds per mile
wilson77 wrote:
70 seconds!? From a coaching perspective I've seen guys and girls drop tremendous amounts of weight looking border line anorexic but still managed to perform extremely well. I believe there is some truth to the lighter you are the faster you are. But there has to be a line when too light undermines performance. I don't know where that line is though.
The important thing to remember is that excess body weight can definitely effect your time. If you loss any body fat hat is able to be lost your will see improvements in your running.
Think about all the things in running we do in order to improve times from the surface we race on to the weight of our shoes.
Someone has calculated just the simple fact of running on mondo track surfaces compared to the cinder tracks would drop about 4 seconds off a mile time. Meaning if they had our all weather surfaces in the 40's and 50's we would not be touting Sir Roger Bannister as the first sub-4 miler!
Bill Bowerman made his own shoes to be as light as he can get them because he believed the weight lost was a compounded weight not carried over the entire race distance even though he only took off an ounce on the shoe.
The fact of the matter is, can we put a consistent value on how effective the weight lost is for every runner in general? I think it is going to effect each runner differently depending on how heavy that runner is to begin with and how fast that runner already runs. Also it depends on your fitness on that specific day/ how well you recovered for your race.
Too many factors to consider when putting an exact value on it, but the important thing is that less weight makes it a whole lot easier to run faster!
Seconds
Good luck. 12:37 is pretty fast, but it MIGHT be within reach if you drop a lot of weight.
I often times ponder this. I'm 220 right now. 5'11". Yes this qualifies me as obese. It is fat too, not muscle.
Consider that last year, at 222 or 223 pounds, I ran 1:40:03 in a half. It was a pretty good effort for me.
Now consider that two years prior, at 195 pounds, I ran 1:26:20 for a half.
My volume of running was similar, my intensity of training paces was similar. Of course my actual paces were slower due to the weight, and I did age two years, but I'll exclude that as a factor.
That means that gaining 27 pounds (195 to 222) cost me 13.5 minutes. Pace for the 1:40 was 7:37, pace for the 1:26:20 was 6:35, or 1:02 per mile.
That's 2.3 seconds per mile. Now I'm sure my training intensities were not exactly the same, and yea maybe going from age 38 to 40 has some effect too. But no doubt the biggest variable was weight gain.
It seems completely reasonable to me that if you have non functional weight to lose (fat), then something like 2s/mi is reasonable.
Now if I lost a ton of weight to put me in the middle of my normal BMI, say 160 pounds, would I really be able to linearly scale my improvement? I seriously doubt it. No way I'd be running a 1:13 half.
The more you loose the faster those miles get without the extra weight. Like, recalculating calories needed to fuel a body at a certain weight. The lighter you get the less calories you need, the faster your times will grow in increased proportions to your weight loss. Your times as "obese" show talent.
Age comes into play as well.
I'm 5'10"
When I was in my 20's, I weighed 133-135
Now in my 50's I weight about 165. I run about 1:22 half marathon. So you're telling me if I lose about 10 lbs, I will cut off about 50 seconds per mile?
So, with that logic I would run a 1:11 at age 54?
Wow
I was actually thinking I might, might be able to break 1:20 at 55.
But with your logic, I guess I'm going to be running 5:30's for 13.1
Whoo hoo
54 y.o. wrote:
Age comes into play as well.
I'm 5'10"
When I was in my 20's, I weighed 133-135
Now in my 50's I weight about 165. I run about 1:22 half marathon. So you're telling me if I lose about 10 lbs, I will cut off about 50 seconds per mile?
So, with that logic I would run a 1:11 at age 54?
Wow
I was actually thinking I might, might be able to break 1:20 at 55.
But with your logic, I guess I'm going to be running 5:30's for 13.1
Whoo hoo
Apparently you lose reading comprehension as you age. I specifically said that I discounted age because it was 38->40. Yea, I suspect age is a bigger factor for 20s->50s. I also said that it couldn't be linear improvement.
Obviously at 5'10 165 you have much less non-functional weight on you.
The rule of thumb is 2 seconds per mile per pound. I believe this is attributed to Tom Osler and that Jack Daniels studied it and it was about right.
I have also heard one minute per pound over a marathon. (Slightly more benefit than the rule of thumb.)
If you want to estimate the effect of weight loss, multiply your current weight by your VDOT from the Daniels table, then divide by your goal weight. That'll give you your projected VDOT.
I disagree that losing weight makes you faster. Obviously if you were 5'10/200+ pounds then dropped to 150 pounds that would make you quite a bit faster, but if I lose 3 pounds I'm gonna chip off 10 seconds per mile? I could take off my jersey, shorts, socks, shoes, and watch and that'd be close to 3 pounds. Does that mean if I run my mile literally bare ass naked I'm gonna PR 10 seconds?
I weigh 142 pounds and am 6'0 (same as Ryan Hall in high school, I must be the next prodigy marathoner). My 5K is 15:47 which is 5:05 pace. If I dropped weight and came back 120 pounds, that's a 22 pound difference. 22 lbs X 3-5 seconds would be between 66-110 seconds per mile off my PR. Thats roughly 3:15 pace, or a 10 minute 5K.
Please stop making up non-sense about losing weight=exponential speed growth, some kids gonna starve and die.
I think you need to use some common sense here. If you are 6 ft and drop to 120 pounds you will be losing muscle not just fat. Losing useless weight like fat will make you faster. There is a limit to how much you can lose before you start shedding those muscles that you use to run.
Ackley wrote:
The rule of thumb is 2 seconds per mile per pound. I believe this is attributed to Tom Osler and that Jack Daniels studied it and it was about right.
I have also heard one minute per pound over a marathon. (Slightly more benefit than the rule of thumb.)
I don't see how this can be accurate. I weigh about 185 (older runner) and can do about a 17:00 5k now. My ideal running weight is about 150 - so that is 35 pounds. So you are telling me I should subtract 70 seconds per mile or about 3 min and 30 seconds for a 5k? So, that would give me about a 13:30?
185 pounds and 17:00 flat? Unless you're like 6'6 i'm calling bs. Especially if you closer to 55-60 than 40 saying you're an older runner.