Master Sgt. Richard Buer, base telephone chief, executes pull-ups during a CrossFit session aboard Al Asad Air Base, Iraq, Nov. 6, 2009. CrossFit combines three different methods of training: cardio, gymnastics and weight lifting, to allow people of all skill levels to participate and work to achieve their training goals. - Master Sgt. Richard Buer, base telephone chief, executes pull-ups during a CrossFit session aboard Al Asad Air Base, Iraq, Nov. 6, 2009. CrossFit combines three different methods of training: cardio, gymnastics and weight lifting, to allow people of all skill levels to participate and work to achieve their training goals.