This exercise is the shoulder raise, it targets the shoulder muscles. What I have Erika do is first stuff is put a slight bend in the elbow, you never want you arms lock right out.
Then raise in the arms up to the side up to shoulder level and then come back down. Also remember to keep the knees nice and bent and the abs always contracted, raising up 2 seconds, coming back down 2 seconds. She’s going to exhale as she raises up and inhale raising down. You can do this exercise 10 times, go through it for 2-3 sets and then move on to the next exercise.