Popsugar Health & Fitness Workouts Best Exercises to Build Muscle in Your Arms Transform Your Upper Body With These 18 Strengthening Exercises 6 July 2018 by Tamara Pridgett View On One Page Photo 2 of 18 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 2 Plank and Straight-Arm Kickback Start in a plank position holding a dumbbell in each hand. Open your feet wider than hip width for a stronger base of support. Lift your left arm behind you as high as you can. Bring the left arm back into plank to complete one rep. Previous Next Start Slideshow Fitness TipsBack ExercisesArm ExercisesStrength TrainingWorkouts