A trainer says these are the four "essential" arm exercises she uses to build muscle

A man performs biceps curl in a gym. He has a heavy dumbbell in his right hand, and his elbow is bent so that the dumbbell is near his shoulder.

I'm a personal trainer and whenever my clients want to build upper-body strength I recommend a workout consisting of four simple dumbbell exercises. They're all beginner-friendly yet challenging and—importantly—they can all be done with a simple pair of dumbbells.

The four essential moves work multiple muscle groups including the anterior deltoids (front of the shoulders), lateral deltoids (side of shoulders), pectorals (chest), trapezius (upper back), biceps, triceps and the core. Here's how you can do them at home.