The single-arm step-up and press builds strength in the lower-body and shoulder area. Isolating one arm at a time also improves balance and stability.
Grab one dumbbell and hold it at shoulder height, your palm facing in. Stand in front of a bench or step, and place one foot firmly on the step.
Pressing into your front heel, push your body up to the step, straightening both legs. As you reach the top, press the dumbbell overhead. Lower the dumbbell back to shoulder and lower back down to starting position.
Don't lean too far forward or use momentum to rise up.