By an "inexperienced" hiker, I refer to one not well versed in mountain trails. Climbing over and around rocks, dealing with scree (loose stones) near scary inclines, and going many miles without an external supply source are what I think of as hiking experience.
It still helps to be physically fit. Hiking ten miles at Bryce Canyon is still an effort comparable to running for an hour or two on the roads. My legs are tired at the end of the day and my feet are sore.