Just watched the MMA episode. It featured Tito Ortiz, Dean Lister, Randy Couture and Bas Rutten. They looked at different strikes, including elbows, punches, and kicks. Randy landed a straight punch that had about 500 pounds (227kg) of pressure behind it, while Bas did a hook that had about 1200 (545kg). Bas also did a Thai-style roundhouse kick that was over 2000 lbs (909kg).
They also showed that a good body slam can generate over 2000 lbs of force. And most surprisingly, that ground-n-pound strikes can generate even more force than standing ones can! Randy was putting out around 2000 lbs of force in some of his seated GnP strikes. I would not have believed that if I hadn't seen it. I really expected those to be much less, but gravity adds quite a bit to those strikes.
Interesting episode, if not strictly "scientific" ie; pretty small test pool.
Curious to know if there is a consistent power difference between straight punches and circular punches.