Bruce Lee did dragon flags often, but they were popularized by Rocky when he was training to beat the hell out of Ivan Drago in Rocky IV. They're exceedingly tough to do, especially if you've never done them before. They're also pretty much the most impressive looking movement you can do in a gym.
Even though they're tough to master, this relatively easy progression takes you from reverse crunches to true dragon flags in no time.
Dragon Flag Progressions
- Reverse Crunch with Counterbalance
- Reverse Crunch with Straight-Leg Heel Tap
- Reverse Crunch to Eccentric Dragon Flag
- Full Dragon Flag