A fellow I know posed the question below:
Q: Hello Gale, I was wondering if you would know how low a percentage of body fat someone could get down to without loosing power? I've got one of the scales that measure body fat and at 167 pounds it says I'm at 13% and wondering how low I should go. Thanks.
A: Good question. The chart below is one that is referenced often, from The American Council on Exercise:
32% or more
26% or more
I did not see any ages associated with these numbers.
The book, "Exercise Physiology" by McArdle, Katch and Katch lists body fat percentages for different types of athletes and professional cyclists (roadies) run 11.6 percent and distance runners go 11.8 percent. For the gals, distance runners go about 17.2 and there are no numbers on the chart for cyclists.
So, back to your personal question - how low can you go without losing power? First, let's assume that your scale accurately measures body fat and you are indeed 13 percent. That puts you on the top end of the athletic scale - a pretty lean guy.
My gut feeling, based on experience and knowing you, is that any lower than 10 percent would cause problems (loss of power). The only real way to know would be to gently work your way down a little at a time and keep tabs on how you feel, speed and power.