Gym equipment not as accurate as they seem

When we're at the gym, we all rely on the machines to count the calories we've burned. But how accurate are they?

After running one mile, it says someone burned 94 calories. But when hooked up to an oxygen analyzer, which counts those calories more accurately, the person actually burned only 75 calories.

The discrepancy occurs because the treadmills only take in pace, weight and age--not your running form, metabolism or specific body type.