The crosswalk is a simultaneous one-arm farmer carry and one-arm overhead carry. Holding a dumbbell, kettlebell or similar in each hand, press one overhead into a stable locked out position and let the other hang at your side.
 
Walk at a brisk pace while keeping the overhead weight stable and maintaining a strong upright posture.
 
Purpose
The crosswalk strengthens and stabilizes the trunk and hips, improves overhead stability, and strengthens the grip and improves grip stamina, and can even be used for some low-level cardiovascular conditioning. It’s a simple way to achieve several purposes in a single exercise.
 
Programming
Generally sets of 6-15 are appropriate, with much higher rep sets with bodyweight for those appropriately capable, and reps as low as 1-3 for weighted sets.