I have found that one pound of weight loss corresponds approximately to a 0.62%…and 0.42% per pound increase in running and biking pace respectfully.
Does anyone have experiance or imperical data to support this. Seems high to me.
Using the N=1 with the one being me, I ran a 24:20 5K yesterday. No laughing please. My Pr is 20:50’ish, again no laughing. Right now I’m about 25 lbs over my PR weight. Using the above data simply losing the 25lbs would put me at a 20:33…a new PR.
Now for the rest of the story. Granted I was not training “Run specific” or with a very large volume by ST standards when I set my 5K PR. However currently my volume is lower, significantly lower, than when I set my PR. To make the above more questionable I’ve pretty much spent teh first 4-5 months of this year with little or no running and have only recently 6-8 weeks been running with any real consistancy. This also includes zero speedwork and even zero tempo.
Soooo I’m wondering if the above is off, I’m not doing or understanding the calculations right, I’m an oddball or maybe I’m just in better shape than I think I am for some reason…the latter being more of a dream than likely reality.
whatever evidence supports this quote (and i am not sure there really is any) i can assure you this:
the relationship between perfomance and body weight, even in a single individual at a contant level of ‘fitness’, in cycling and running is no way a linear relationship.
so based on this alone, the quote of “X percent improvement” per pound body weight loss is most certainly incorrect.
I’ve heard that a pound is worth 4 seconds per mile. So 5 pounds would equal 5+ minutes in a marathon. I suspect there are limits to this–only linear in certain ranges and when your body fat gets low enough losing weight may be negative. Also some people are more limited by AT than by V02max–especially for a 5k
On the bike it’s definately driven by the course profile–more of an issue for hilly courses than flat. Also just losing weight without training won’t translate into fitness.
I wouldn’t worry about it–lose fat you’ll be faster so why not?
So, as a 212 lb Clydesdale who ran a 1:34 1/2 marathon this weekend and a 19:45 5K the next day, if I lose 10 lbs before the Chicago Marathon on Oct 7 I will run 10 minutes faster than I would now? What about your cardio system being able to handle the increased pace?
What about your cardio system being able to handle the increased pace?
Your fitness allows for a given rate of work which you use to move your mass, that determines your pace. If you lower your mass, same fitness, your pace should increase.
So, as a 212 lb Clydesdale who ran a 1:34 1/2 marathon this weekend and a 19:45 5K the next day, if I lose 10 lbs before the Chicago Marathon on Oct 7 I will run 10 minutes faster than I would now? What about your cardio system being able to handle the increased pace?
uh, since the workload is the same, your cardio system is being stressed at the same level. that’s the underlying concept here.
Another question for the masses…What effect does losing 5% of your body weight in a short (3 week) period of time do to overall performance? I ask because after this weekend’s 1/2 IM I was thinking of trying to cut 10lbs in 10 days whiel training to get down to 200 for Chicago. Probably not the smartest thing in the world, but as someone said lower mass and same fitness = faster.
But there’s no way to determine whether the improvement was from training or from weight loss. About the only way I can see determining this is to instantly put on “X” amount of weight and seeing the difference in race times. The other way would be to do a long term study on a “Trained” individual that has a constant training plan that has in the past shown no improvement and have that person lose/gain the weight.
Since I’m A) losing weight and B) training, hopefully for improvement there’s no way to tell if the improvement was from training or weight loss.
In the “Real world” it doesn’t really matter, but from a future “This training caused this improvement” standpoint it would be nice to know what and how much of the improvement was from weight loss and what was from training.
OK, just lose the weight without training, then run another 5K on a similar course and conditions. IOW, don’t run at all while losing the weight, then train for 6 weeks by just running consistently, but no speedwork or tempo runs.
I ask because after this weekend’s 1/2 IM I was thinking of trying to cut 10lbs in 10 days whiel training to get down to 200 for Chicago.
Personally I’d say bad idea. 10lbs in 10days is most likely 6-7lbs of water and 2-3 lbs of fat. In order to lose 10lbs of fat in 10 days you’d have to burn a deficit of around 35,000 calories or 3,500 calories a day. In VERY rough numbers at 200lbs this would be akin to not eating anything for 10 days and running around 7-10 miles a day assuming 2000-2200 basil. Of course under those conditions I’m guessing you’d also be eating a bunch of muscle as well so still wouldn’t be losing 10 lbs of fat.
But I’m no nutritional expert…but I slept at a Holiday Inn once.
Yeah, good call. I drink about a gallon of water a day, so my “real” weight might be closer to 208 or so. I might try to run a 750-1000 calorie a day deficit for 10 days of training and see how low I go and be happy with that. Any loss will help.
IOW, don’t run at all while losing the weight, then train for 6 weeks by just running consistently, but no speedwork or tempo runs.
About the only way I can envision this working is if I “duplicate” the prior 6 months or so before my last 5K. IOW do only sporadic training for 6 months and then 6-8 weeks similar to what I’ve been doing for the last 6-8 weeks. Again a guess, but say I lost the weight in 10-12 weeks and did nothing I’m not sure I would be as “Untrained” as I was when I started training again.
Also I’m really not all that interested in experimenting on myself as much as I’m interested in if the data is correct or how the numbers where arrived at.
“I’m really not all that interested in experimenting on myself as much as I’m interested in if the data is correct or how the numbers where arrived at.”
You really would need to address your questions to the author of the study.
I’m sure those with an actual education and experience with weight loss will be by shortly, but the threat of an imminent contradictory expert opinion has never stopped me before…
Assuming you don’t intend to dehydrate yourself severely to contribute to the 10lbs, I can’t imagine how someone who can run a 1:34 HM could possibly shed 10lbs of fat/muscle in 10 days off a 212 lb body. Even if you were completely sedentary and on a 100% crap diet, I’m not sure you could lose 10lbs in 10 days. You’d have to burn 3500 calories more per day then you take in every day for 10 days. Not possible to do safely, I suspect.
Carefully controlling diet for a 500-1000 calorie deficit per day could get you a 1-3 pounds but you might not feel particularly strong on race day.
Thinking outside the box:
*you could do the colon cleansing thing - liquid diet, colonics, etc. I think I read that we each carry about 8lbs of, errr, waste-matter, in our lower GI tract that can be flushed, though it builds back up again once you start consuming real food. I’ll keep my 8 pounds, thanks…
amputation?
how long is your hair? might be a pound there if its shaggy…
I see myself naked every day, so I know I have some weight to lose…Ok, seriously, I have photos of me on my blog and there is some weight to drop there, I jsut don’t know how much I can do from the weekend until a week before Chicago when full blown taper mode starts. Maybe 4-5 lbs, maybe 6-7 who knows. I’ll also ramp my mileage up a bit too, so I know I’ll burn more calories there…
I am by no means lean. As a 5’11 former linebacker I’ll never be lean, but people can look at the photos on my blog and tell me if I am or not. I have no idea. That said, my BF % might be around 15% or so.