About Accuracy

When you are measuring changes in your own fitness, accuracy isn't as important as repeatability. To illustrate, let’s use some real numbers. To keep it simple, we’ll use a measurement that we’re all familiar with – body weight. In this illustration, we’ll take a look at Fred and Sam, two friends who are both starting an exercise program. At the beginning of week 1 Fred gets on his bathroom scales and reads 200 lbs. Likewise, Sam weighs himself on his own bathroom scales and reads 200 lbs. However, neither of these bathroom scales is accurate. Fred’s bathroom scales read 2 lbs too low, so Fred actually weights 202 lbs. In contrast, Sam’s scales read 2 lbs too high, so Sam really only weighs 198 lbs.

After a week of exercise Fred weighs himself and is pleased to see 198 lbs register on his scales. Fred has lost 2 lbs. Even though Fred thinks it was the 2 lbs between 200 and 198, it was actually the 2 lbs between 202 and 200. Still, even though the scales are inaccurate, they accurately show the change – a loss of 2 lbs. Things didn’t work out quite so well for Sam. After a week he weighed himself again and saw no change; his scales still read 200 lbs.

When Fred and Sam get together to compare their weights, Fred brags that he now weighs less than Sam. Fred believes he weighs 198 lbs and that Sam weighs 200 lbs. The fact is that Fred weighs 200 lbs and Sam weighs only 198 lbs. This illustrates that while these inaccurate scales accurately report the changes in body weight, they cannot be depended on when making comparisons to other people.

The field tests presented by Lock On Fitness are great for measuring changes that are happening within your own body but the accuracy of laboratory tests are needed when making comparisons between two or more people.