Cofferdam A cofferdam is a temporary enclosure built within, or in pairs across, a body of water and constructed to allow the enclosed area to be pumped out, creating a dry work environment for the major work to proceed.
Push ups primarily work the upper body muscles, with some core muscles being worked by providing secondary support. The main muscles worked in the traditional push up are the shoulder (deltoids), chest (pectorals) and triceps. There are many variations that you can use to spice up a push up routine and target specific muscle groups. Hand placement variations in push ups are one way to add variety. Placing your hands wider than your shoulders will work chest muscles more. The diamond hand position works the triceps. You do the diamond by placing the thumb and forefingers of both hands together in a diamond shape with your hands flat on the ground. Foot placement has a huge impact on the level of challenge with push ups.
The push-up excercise requires many muscle groups, but the primary muscle group has to be the chest muscles. the chest includes the pectoralis major and minor. These are the 2 large chest muscles and mainly the pushing muscle group of the upper body. As you are pushing and lowering your body during a push up, the pectoralis major is doing most of the work. As a result, these 2 muscles become very strong and can become defined lean muscle after doing push-ups regularly.