正手/反手引體上升 分別練乜...?

正手引體上升 is called pull-up,反手引體上升 is called chin-up, they are both target for the back muscle and some arm muscle. Many people believe that chin-up involve more arm muscle than the pull-up, and more difficult to do. In US navy and army recruit will ask people to do pull-ups. Bodybuilders suggested to do a chin-up, because they involve more arm muscle.

http://www.takesport.idv.tw/gym/workout/back/back.asp

都係練背