Pushups are a classic exercise that you can do almost anywhere -- at the gym, at home or at your office. They can be done with just your body weight, or you can add supplemental weight on your back, change your hand position or create an unstable surface in order to increase the challenge. You can also do pushups on a decline -- elevating your feet above your heart -- to make this already challenging exercise even harder.
Pushups are a compound exercise, meaning they work more than one muscle group at a time. In fact, pushups work almost all the major muscle groups in the body and many of the smaller stabilizer muscles. The primary muscles worked during a pushup are the pectoral muscles in the chest, the deltoid muscles of the shoulders and the triceps muscle in the upper arm. With proper technique, the abdominal muscles should be activated to keep the midsection stabilized and the leg muscles should be contracted.
The basic form for a decline pushup is not much different from a regular pushup, except for your feet being elevated above your heart. A weight bench makes the perfect surface to elevate the feet, but if you don't have access to one, you can also use a step, or do your pushups on a hill at a park. Space your hands a little wider than shoulder-distance apart, place your feet up on the bench with your toes curled under and slowly lower your chest down towards the floor by bending your elbows out to the side. Remember to keep the abdominal muscles tight, and don't go so low that you won't be able to press yourself back up again.
Decline Pushups vs. Regular Pushups
Decline pushups are significantly more challenging than regular pushups, so they should only be executed by advanced exercisers who have already mastered a regular pushup. Besides an increase in challenge, the difference between the two types of pushups is in the part of the pectoral muscles that gets worked the most. According to exercise instruction website ExRx.net, elevating the feet considerably will not activate the sternal head of the pectoral muscle, while lower elevations will activate both the sternal head and the clavicular head. These are the lower and upper sections of the pectoral muscle. For most people, this distinction won't make a difference, but if you are an advanced bodybuilder and are concerned with which head of your pectoral muscles get worked the most, then you should take this into consideration.
The height of the elevation of your feet during the exercise makes a difference. The higher your feet are, the more challenging the pushup will be. Start by increasing the height of your feet by a few inches -- you can prop your feet up on some weights or a small step -- and gradually increase the angle of the decline as you get stronger. To increase the challenge of a decline pushup even more, lift one leg off the bench as you go into your pushup and leave it elevated for a few repetitions. Then switch sides, elevating your other leg.