i've been doing the itread workouts, and unfortunately, my treadmill is an older model and although it does incline, it doesn't indicate the percentage of the grade. is there a "standard" highest grade that most treadmills follow? or are there treadmills that go up to all different grades? i'm just not sure if i'm hitting the right mark when i have to go to 5% or 9%, etc. basically i just make sure that i'm higher or lower than where i was previously, depending on what i'm supposed to do.
thanks!
thanks!