The single-arm cable lateral raise is an isolation exercise targeting the shoulders, specifically the medial deltoid. This movement also hits the traps and upper back, and allows you to focus on each side independently. Because grip is a limitation, it is usually performed for moderate to high reps, like at least 8-12 reps per set, as part of an upper body or shoulders-focused workout.
Build and strengthen the deltoids, and middle deltoids in particular
Cable encourages strict form without excess momentum