Pull-ups and chin-ups are two useful body weight exercises that can be done anywhere there is a bar to hold your body weight. Pull-ups are beneficial for any type of climbing in parkour, and are very beneficial for wrist, forearm, shoulder, and upper-back strength. Chin-ups are beneficial also for parkour, and are beneficial for the same set of parts of the body, but also hits the bicep more than the pull-ups. You should have your hands shoulder width apart when grabbing the bar, and during the process of pulling up towards the bar. Your chin should be going over the bar, regardless of doing either the pull-up or chin-up. Also, it is important to note, that you are not use your own momentum to do either the pull-up or chin-up, it simply is cheating yourself of the exercise.