Guide :Exercise & Fitness : TF3i Folding Treadmill
When keeping speed, incline, etc equal, I find some treadmills harder to run on than others. Why?
I find, for instance, than on some machines I can easily run 5 to 7 miles at a good pace (6.7 - 7 mpg) while others I am exhausted after 2.5 miles! Same incline, same speeds, etc. What is the difference?