This is a bomabastic, risk-taking version of the side kick designed to cover lots of ground and apply lots of momentum if you successfully land it on the opponent. It is done by none other than Bruce Lee. This is a good example of a kick that you shouldn't do if you've screwed up your knees and hip.
The following is a video I just found off youtube. Aside from the irritating music (mute your volume), the side kick (in the later half of the video), is a good example of a conservative kick that preserves COG in order to allow practitioner to return fire with hand strikes. Notice the stylistic nuances - they are not entirely necessary to perform the side kick, but don't overly detract from it if you know how to land strikes on the opponent. This is a kick that will help reduce joint and hip injuries.
Won-hyo Side Kick
Martial Arts Sources: Bruce Lee