The TRX Chest press is one of the best ways to build upper body strength.  This is a very simple exercise to set up, but depending on you angle, it can be a very difficult exercise to perform.  I like to adjust my straps to around mid-calf length, and then adjust my body to get a good angle that will really challenge my muscles.  The TRX Chest Press not only works out your chest, but it also works out your core, because you have to keep it tight the whole time.

The reason this workout is so affective and different then doing a normal push-up, is because you have to stabilize yourself through the workout, which works out all the little supporting muscles around you main chest muscles.  Here is a video to show how to properly do the TRX Chest Press.