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.
Pectoralis Major. These are the two large chest muscles primarily the pushing muscles of the upper body. It makes up most of the upper body. As you raise and lower your body during a push-up, the pectoralis major is doing most of the work to raise and lower your body.Deltoids.he following steps explain how to do a push-up: 1  Lower your body down on to the floor or a carpeted floor with your palms under your shoulders-slightly wider than shoulder width. 2  Keep your feet close together and dig your toes into the floor helping to stabilize the lower part of your body.