The Garmin Enduro 4 GPS smartwatch adds grade-adjusted pace workouts, which set pace targets that shift with the incline or decline of the trail. On a steep climb the target eases off to match the grade, and on a descent it asks for more speed, so effort stays where the training plan put it. Rolling grade-adjusted pace keeps a running average that accounts for every hill, so the number on the wrist reflects effort across a whole trail run instead of raw speed. What Our Gearhead(R) Experts Are Saying:"I loaded every aid station and cut-off for my last 50K into the course planner, and the watch showed the distance to the next one at a glance all day. I quit doing aid-station math in my head right around the miles where that math starts falling apart."