Bench press helps to expand chest muscles. Actually, it is the most common and well-known exercise.
If someone went to the gym, they would have high probability of doing bench press.
Bench press consists of three types in accordance with degrees.
If bench is upper than 180 degress from the ground, it's called incline bench press. If bench is 180 degress from the ground, it's called flat bench press which is generally called bench press. If bench is lower than 180 degrees from the ground, it's called decline bench press.
Therefore, I'm going to explain how to do flat bench press ( = bench press ).
At first, you should lie down on a bench and you should make your back like an arch which means your chest should be opened to get constracted and stertched as much as you can. After that, you should grip a bar a little bit wider than your shoulder's width and lift the bar safely and slowly.
Secondly, you should down the bar slowly until the bar almost touch your chest. When you lift the bar, you should feel that your chest is constracting. At the end of the exercise, your elbow must not to stretch all. Otherwise, your triceps are going to get more tired. That's how you do bench press.