I was browsing through BJJ videos yesterday and ended on this one [ame="http://www.youtube.com/watch?v=wNJk_OEO5MU&feature=my_liked_videos&list=LLRINkxuBnVJw8X0Z5CP3ESQ"]Brazilian Jiu Jitsu: The Animals Drill - YouTube[/ame] I really liked the drill and I thought I might start doing it for a while once a day. However, I wanted to ask you guys about it, because I know martial arts have a tendency to develop drills out of aesthetic principles that are often inefficient or even bad for your body. For instance, I learned some warming up and stretching drills with my Shaolin shifu that were very bad on the joints, and I don't want to make mistakes like that again. So to the point: Do you think these drills are "safe" to practice regularly, and that they'll help with BJJ? Any one that strikes you as bad use of body mechanics?