Hi - this is an interesting video, unfortunately in Chinese, showing how Zhang Zhi Jun's Taiji punch differs from the punch from "normal" martial artists (probably trained in sanda). He is in his 60s and quite well known for actually having fought in public and against some Shiorinji Kempo Challengers from Japan in the 1980s.
His punch is in terms of pressure ranks at the bottom which is bad, but the two things that they found, the vibration from the punch lasted much longer (i.e. the internal organs shook for longer causing more damage) and that the his use of all his muscles was pretty even and integrated (whole body power), measured using electrical readings compared to the others.
http://bugu.cntv.cn/life/science/zou...2/100843.shtml