Body Fat & Skinfold Calipers

I am an amateur competitive cyclist (road, crit, track- though I am not exactly “competitive” on the track :rolleyes: ). We don’t have 6-figure sponsorships or team trainers, like the pros. We are on our own for this stuff. This certainly isn’t a cycling board, but I suspect these are concepts that will translate well for a lot of more dedicated fitness types here; so I am soliciting you gentlemen for some guidance on how to go about assessing accurate body fat measurement.

I’m obviously very fit in a general sense, but I’m actually a little on the beefier side for what I do. I’m primarily a climbing specialist; that is, on those races or stages where there is significant elevation gain, I am the teammate looked upon to bring in the win. I do OK, and my wattage figures are very high; so high, in fact, that I should have better climb times than I am putting up currently. I’m actively trying to discover holes in my training program, and have found some strength deficiencies: hip flexors are weak, and I haven’t had my hips rotated forward enough to bring the full power of my glutes into the pedal stroke. I’m actively addressing those issues, both with training and with changing my crank length and saddle type on the bike. I am already seeing some improvements in my segment time.

I’m left with strength:weight ratio. At 150lbs and 5’7", I am heavy. Other climb specialists (worth their weight) at my height are closer to 130-135, but they’re very slender and their power output is often up to 25+ watts less than mine for similar segment time. They weigh less, and so do not have to mash as much energy into the cranks to drive up hills at the same pace. If I weighed less, but managed to maintain my current power, I’d absolutely dominate the climbs; I just don’t seem to have a lot of fat to spare. The largest bulk of my weight, sayeth the mirror, is in my legs/glutes. I’ve always justified my weight by pointing out the fact that I wear a S jersey, but a M bib (shorts).

I’ve read accounts of body builders with single-digit body fat percentages actually getting negative percentage output from the common formulas, because at these levels the formulas simply don’t work. I haven’t tried it, and nobody else on my team has ever bothered to try to calculate theirs, as they’re all even skinnier than I. It’s just not something cyclists ever really seem to need to watch. But I seem to be special; if my body fat percentage is higher than I think, I can immediately improve my climb times simply by assessing how much fat I have to lose, and losing it.

I explain all of this for your interest, if it is interesting, but mostly to preclude the inevitable “wat diff does it make wat u weigh bro only the mirror matters rite.” In fact, weight matters a lot, in my case. So, to the point: What kind of accuracy can I expect from skinfold calipers? I’m sure my percentage is closer to 10% than 5. Does this issue with the equation falling apart only happen at the very low end? Is there any way to mitigate it? Should I bother investing in a caliper? What other home-user methods work well?

Thank you,

Dead

Skin fold thickness is not a great method for determining body fat percentage with the kind of accuracy you have in mind. It’s just cheap. Might provide you with some relative value, but in absolute terms it’s not going to be that helpful. Check a physiology lab at any university close to you…they may have plethysmography equipment. A more likely approach would be to call a nutritionist at your local hospital. They can likely steer you in the right direction. Many hospitals will be able to calculate an accurate body fat percentage via ultrasound or DEXA scanning.

I tend to use and recommend calipers for changes in absolute terms vs accuracy of BF% as you indicate abobe. However, Quality calipers done by a trained person correlated well to under water weighing. But that’s also the downfall, not easily reproducible and hard to measure in individuals with a BMI above 35 and or very lean. Wider margin of error also I recall.

In the very lean, if the the person goes from 8% to 6%, with a margin of error of +/- 3% say, it’s of little value in terms of accuracy of actual BF%.

You guys use DEXA?

LOLOLOLOL

Isn’t the only real accurate body fat test the buoyancy test?