Accuracy of exercise equipment?

akgrown4

I remember reading about how most exercise equipment just assumes you are a "normal" person in terms of weight and age, and calculates calorie expenditures based on that, but for those over the norm, you would be burning more than the machine says. I was wondering if anyone knows of any machines that account for weight, age, gender, those kinds of things to get a more accurate calorie burn. Or if anyone knows how accurate the online calculators are that take those things into account. I've been using http://www.healthstatus.com/calculate/cbc to figure what I burn after exercising.