Archived Forum Advice, Vol. 566

By Steve Maxwell

Recovered by Dave Wardman

Dkaler,

At West Chester State as a physical education major, back in the early 70's, I took part in a study in the accuracy of skin fold calipers. All the guys on the wrestling team were guinea pigs for the experiment.We were tatooed with little ink dots at 5 sites so it would be easier for the testers, all trained athletic trainers,to duplicate the measurements. There was as much as a 5% standard deviation from measurement to measurement with the same person taking the measurements.When different people took the measurements the test was even more inaccurate.Assuming your tester was competent,the best you could hope for would be 5% leaner or fatter than the results indicate.5% is a huge error.Forget about skin fold as a way of measuring percent body fat.

Electical impedance is notoriously biased toward lean people. The leaner you are ,the more inaccurate the results. The gold standard is under water weighing. Even this can be flawed if certain things are not factored in such as residual volume in the lungs.Once,after being measured at 5.3% fat with under water weighing,I was measured at 15% by electrical impedance only two days later!

The only standard that one really needs is the mirror,how your clothes fit and how you feel about the way you look.

Steve Maxwell