When I was running marathons in the 80’s, my body weight then was 137-140 pounds. I was “lean and mean” and did not have so much fat in my body then and I was running 3:30:00-3:45:00 hours for the marathon; 1:30:00-1:40:00 hours for the 20K; and 39:00-42:00 minutes for the 10K. At present, my body weight is 155 pounds and I am trying to reduce weight (by running) in order to be competetive and reduce my PR time in future races.
In my readings and reasearch on running, for the elite runners (men), their racing body weight is determined by this widely used “rule of thumb” which is the 2:1 ratio—two pounds of the body weight for every inch in height. As applied to my body, my height is 67 inches multiplied by 2, and the result is 134 pounds! For the advanced runners & weekend runner (men) who wants to compete in their respective age categories, the ideal racing body weight is computed as the total of the 2:1 ratio plus 10% of the body weight. As applied to my body, the product of 2:1 ratio is 134 pounds plus 10% (of 134 lbs) is equivalent to 147.4 pounds. If I am seriously considering myself in this category of advanced runners, I should be able to reduce at least 7 pounds from my present weight.
For elite women runners, the formula that works very accurate to men’s elite does not apply to them. Women have a different body fat and body muscle make-up. But this is a suggested reference as the racing body weight for female elite runners—use 5 feet height as the base height and the equivalent of 81 pounds as the base weight. For every inch increment in height means an additional of 5 pounds from 81 pounds (base weight). As an example, the average racing body weight of a 5′ 4″ feet woman should be 81 plus 20 which is 101 pounds. For the advanced and weekend runner who wants to compete in their respective age categories, the suggested formula/reference is the same with the women elite runners but the base height is 5 feet at 90 pounds as the base weight and for every increment of one inch means an additional 5 pounds from 90 pounds. As an example, for a 5′ 6″ feet woman, her average racing body weight should be 90 pounds plus 30, which is equivalent to 120 pounds.
I hope this information will be helpful to those who want to excel in the sports of running. Keep on running!