The exercise known as a pushup (also called press-up) is one of the most common and popular upper body exercises, and is performed by a variety of people, from schoolchildren in physical education classes to athletes training for the Olympics. There are a large number of pushup variations you can use to strengthen, build and tone your upper body muscles, making the pushup one of the most versatile body weight exercises around.

Multiple Muscles

If you're looking to exercise multiple muscles at once, then the pushup is the one for you. A pushup is a closed chain compound exercise, which means that your body is in contact with the floor and more than one joint is involved at the same time. Pushups involve horizontal flexion of the shoulder joint and extension of the elbow, which utilizes the pectoralis major, anterior deltoid and triceps respectively. When you perform pushups, your abdominal muscles keep your spine rigid, while the hip flexor muscles -- the iliopsoas -- and the quadriceps of the thighs hold your legs in place.

Your Choice

You won't know which to choose first. There are many pushup variations for you to try. While all of the variations involve the muscles of the chest, shoulders and arms, different variations stress these muscles to greater or lesser degrees.

In diamond pushups, placing your hands together while performing the exercise puts an emphasis on the triceps at the back of your arm. In foot-elevated pushups, placing your feet on a raised platform (for example, a chair or exercise bench) will put more weight on your hands and make the exercise more challenging. In wide pushups, the wider your hands are, the greater the range of movement at the shoulders and the more work will be required from your chest and shoulder muscles. Try placing your hands 1.5 shoulder widths apart. In stability ball pushups, placing your hands or feet on a stability ball increases the balance demand and can help improve shoulder and core stability by making your limbs wobble.

Handstand pushups are demanding exercises performed in a vertical handstand position, either balanced against a wall or unsupported. These pushups emphasize your shoulders and are a very advanced variation.

The Wow Factor

Variety is the spice of life, so make pushups more demanding by performing them using other training equipment. Wearing a weighted vest adds more resistance to your pushups, as does holding a rubber exercise band behind your back. Pushups can also be performed using special pushup handles, which can increase the depth of your pushup and make the exercise more demanding.

The Glory

The "Guinness Book of World Records" has published the names of the most notable pushup artists in the world. For the most pushups in five minutes: 441, to be exact, was won by Giuseppe Cusano in 2003. Charles Servizio holds the record for most pushups in 24 hours: 46,001. The non-stop pushup title went to Minoru Yoshida in 1980 for 10,507. And in 1989, Paddy Doyle was recognized for the most pushups completed in a year: 1,500,230.

Pushup Standards

Pushups are used to assess fitness and strength in branches of the military, the police and the fire service. Performance is graded according to age and gender, but participants are expected to be able to exceed the age-group averages. Pushups are also often included in health screenings and physicals to assess muscular endurance.