I have heard different things on weight and its effects on ones performance. Obviously if you are carrying extra weight you won't travel as fast as someone who is lighter.
As for myself I ran 4:38 for 1 mile and 26:20 for 5 miles while carrying 160lbs on a 5'10 frame. I am sure that with more discipline in training and diet I could be 5-10lbs lighter, perhaps more. If anyone can provide some insight it is much appreciated.
There's a table for this somewhere. Every extra lb costs you a second per mile or something. But that's my memory of a table that I saw 5 years ago.
So wait, if Bekele dropped down to 115 instead of 122, he'd run 12:15 for 5,000m? Who woulda' thought?
Body weight is not an aboslute. Many more factors come into play, such as body composition, strength-to-weight ratio, etc.
Obviously the weight cannot be the same lean muscle mass which helps one run fast, otherwise at zero pounds one would be infinitely fast. Wait, maybe that is true. But I'm glad you're a moron who failed to recognise that there is a correlation between excess weight and speed.
No, Einstein said we needed to gain weight to run fast. As an object's mass approaches infinity, its energy becomes infinitely great as well. Great excuse to hit the BK down the block...then TB...and MD's.
For an event that is (almost) purely aerobic, you can estimate from relative VO2max. This won't work well for mile and shorter, as it's 30% anaerobic.
From Dr. Daniels "Oxygen Power" equations, which I turned into an excel spreadsheet, 26:20 for 5 miles comes to a VO2 of 60.79, which is 93.7% of the relative VO2max of 64.87. Losing 10 pounds from 160 would have the effect of increasing the relative VO2max by 6.66%, which yields a new relative VO2max of 69.19. Assuming that the weight loss was not due to increased training and that the weight loss did not cause muscle weakness that might reduce performance, the new VO2max would implay a performance for 5 miles of just under 25:00.