I am a geologist, now retired. I am planning to through hike the Appalachian Trail in 2017. Hiking Hermit Trail in the Grand Canyon was my first preparation hike. I am still working on my gear for the long trail. I am also planning on doing some section hikes on the A.T. this year to try to stay (get?) in shape. I feel good about the Grand Canyon hike, and while I was pretty slow coming out (13 hours for the 9.7 mile hike) I did not have time to get my trail legs and feel like I would have gotten stronger with more trail time. I was not sore or particularly tired when getting back to the rim.