Updated December 16, 2014.
The push up may just be the perfect total body exercise that builds both upper body and core strength. Done properly, it is a compound exercise that uses muscles in the chest, shoulders, triceps, back, abs and even the legs.

How to Do a Perfect Push Up

• Get on the floor and position your hands slightly wider than your shoulders.
• Raise up onto your toes so you are balanced on your hands and toes.
• Keep your body in a straight line from head to toe without sagging in the middle or arching your back.

• Your feet can be close together or a bit wider depending upon what is most comfortable for you.
• Before you begin any movement, contract your abs and tighten your core by pulling your belly button toward your spine.
• Keep a tight core throughout the entire push up.
• Inhale as you slowly bend your elbows and lower yourself until your elbows are at a 90 degree angle.
• Exhale as you begin pushing back up to the start position
• Don't lock out the elbows; keep them slightly bent.
• Repeat for as many repetitions as your workout routine requires.

How to Do More Push Ups

You can use a few simple strategies to build your strength and endurance in order to do more push ups. This is useful for those who have to pass a fitness test (such as the Army Physical Fitness Test). It takes time, effort and a systematic approach, but doing more push ups is not impossible.

Push Up Variations

• Push Up Lat Row
  The push up is nearly perfect all by itself, but add a couple of dumbbells to the movement and you have a complete upper body workout. This variation adds alternating dumbbell lat rows to the top of each rep. This modification increases the intensity of the exercise, activates the core stabilizers and engages the latissimus dorsi (back) muscles.

• Stability Ball Push Ups
  If you are ready to move beyond the basic push and add some core stability work try stability ball push ups. This variation of the push up increases the difficulty and effectiveness of the standard push up. Adding the balance requirement takes some practice an good core strength, so make sure you can do about 20 basic push ups before trying these.
• Alternating Medicine Ball Push Up
  This variation adds core stability as well as a modified range of motion during the basic push up movement. Roll the medicine ball between each hand after a reps and add a new balance challenge.
• Incline Push Ups
  If a standard push up is too difficult, you can start by doing push ups against a wall, a table or a sturdy chair. Stand several feet away from the object you are using and use the same push up technique as above to lower yourself until the elbows are 90 degrees and then raise back up. Keep you core tight the whole time.
• Bent Knee Push Ups
  This is a modified version of the standard push up performed on the knees rather than on the toes. Be sure to keep the knees, hips and shoulders all in a straight line; most people have a tendency to bend at the hips as though you are bowing, but this is incorrect technique.
• Decline Push Ups
  This is a more difficult push up, performed with the feet raised up on a box or bench. You can adjust the box height to increase or decrease the resistance using just your body weight.
• Clapping Push Up
  This is a plyometric exercise in which you push yourself up with enough power so that your hands come off the floor and you clap in midair. This exercise is not for novice exercisers. You can get injured very easily if you haven't worked up to these one at a time.
• Medicine Ball Push Up
  Perform a standard push up with one hand one top of a medicine ball. This works the shoulder in a slightly different range of motion which increases shoulder stability.
• Diamond Push Up
  The diamond push up is done with your hands close together; with the index fingers and thumbs of one hand touching touching the other hand and making a diamond shape. You then do push ups with your hands touching the center of your chest and elbows close to your sides during each rep.