The grades are summarized in the table, but the angles shown in the graph are more revealing. Cleated hiking shoes are recommended on our trails. Tennis shoes are great up and down on firm footing like concrete or paved roads, but on loose gravel they are prone to slip. Tennis and walking shoes are very comfortable, but their tread just doesn t catch very well on a loose granite slope. My old Vibram lug soles do a much better job gripping.
Edges dig in when sidestepping down and the soles are less flexible over rocky trails.
A walking stick can be a great help offering brace and balance on steep grades. Seems steeper than easing down the house stairs on your butt Angle of Repose. Incidentally, I like going up better than down.