The classic pushup targets the chest muscles, but a slight change of your hand placement makes the triceps muscles the primary movers. To target this distinctive three-part muscle group at the back of your upper arm, do diamond pushups with your hands close together. Include the move in bootcamp, circuit or arm workout routines.
To do a diamond, or close-grip, pushup, get into the top of a pushup position. Move your hands close together under your chest so the index fingers and thumbs almost touch -- forming a diamond shape. Bend your elbows to lower your body toward the ground. Keep your triceps close to your trunk as you maintain a rigid torso. Extend your elbows to return to the starting position. A complete set consists of eight to 12 repetitions of this exercise -- more if you are training for endurance. The triceps pushup is extremely challenging, so you may need to modify it at first. Try placing you knees in the mat as you bend and extend your elbows or do the exercise against a wall.
The triceps at the back of the upper arm are the primary muscle worked during the diamond pushup. The triceps are responsible for extension of your elbow, which happens when you straighten your arms to rise up from the bottom of the diamond pushup. Toned triceps show up as a horseshoe shape at the back your arms.
The pectoralis major, the primary, fanlike muscle of the chest, assists the triceps in executing the diamond pushup. This muscle has an upper and a lower head, both of which are activated during the exercise. The front of the three-part muscle that caps the shoulder, called the anterior deltoid, also helps you complete the diamond pushup.
One reason the pushup is a classic go-to exercise is because it works so many different muscles as stabilizers. The diamond pushup is no different. You use the biceps at the front of the arm to keep the elbow joint stable. The rectus abdominis, the front superficial abdominal muscle, and the obliques at the sides of the abdomen also work to keep your torso and hips from sagging as you push up and down. Your quadriceps at the front of the thighs further assist in stabilization.