The barbell bench press, or "bench press," is a fundamental lift that serves as one of several "core" exercises. The name "core exercise" is not given to it because it's an abdominal exercise, but because it is an exercise that works several large muscle areas and the movement involves more than one joint. The bench press is fundamental because it can be used to train for a variety of sports and activities. Practicing the bench press can look easy, but there are some underlying techniques that are important to understand.
The bench-press exercise involves lying face up on a bench and slowly lowering and raising a barbell to and from your chest. The primary muscles involved are the pectoral major, anterior deltoid and triceps. These muscles, working together, can generate an enormous amount of force if trained properly.
To prevent injury, the bar should never be bounced off the chest. This move can be extremely dangerous due to momentum changes in the bar as it accelerates toward the chest. It's best not to allow the bar to depress the breastbone whatsoever. By slowly lowering the bar and allowing it to just barely touch the chest, your shoulders will be exposed to much less stress.
The grip width and where the bar touches the chest are really the same issue. If you decide to grip the bar slightly wider, you will have to touch the bar closer to the top of the breastbone. As you bring your hands in closer on the bar, such as in a close grip bench press (shoulder width grip), the bar will touch more toward the bottom of the breastbone.
When performing the bench press, it's extremely important to have a spotter, especially if you are unsure how much weight you can handle. Either one spotter should stand behind the bar or two spotters should stand near both ends of the bar. Always make sure everyone is paying attention to the individual who is bench pressing. With a spotter, help can be offered when the weight cannot be lifted.