Below is taken from a post by a friend in a thread on a closed Facebook group. He was gracious enough to answer my question about Sanda (散打) in great detail. Reproduced here for my own future reference (and possibly for other people’s) with his explicit permission.
Sanda is a relatively recent development in the long history of Chinese martial arts. I’ve met 1st generation Chinese Sanda fighters and coaches, namely Michael Li (李永謙教練) and Prof. Li Tai-liang (李泰良教授), the latter is F*’s master.
*another member of the group.
Michael Li and Prof. Li have extensive traditional Chinese martial arts backgrounds. Moreover, both of them graduated from Beijing Sports University where they had specialized in martial arts. According to both of them, the sport of Sanda was created in the late 70s under the direction of Prof. Zhang Wenguang (張文光教授) in order to put fighting back into wushu, which had become by then mainly a performance art. Beijing Sports University gathered traditional Chinese martial arts masters of several systems to demonstrate and teach their fighting methods. The result of their research and development was the incorporation of techniques suitable for competition in leitai (擂台), basically a square platform fighting arena. Since Sanda competitors wear padded gloves, joint locks seen in many traditional martial arts were eschewed in favor of techniques from boxing and Chinese wrestling (摔跤 shuai jiao), especially since throws scored more points. As for kicking, the preferred kicking technique in Sanda is the side thrust kick (側踹腿 ce chuai tui) since it can easily push the opponent to the ground or off the leitai and score more points.
So is Sanda Taiji, or is Taiji Sanda? Although Sanda has its roots in traditional Chinese fighting methods, it has became a sport of its own. Indeed, many fighting techniques in Sanda look like ones seen in Taiji and vice versa. However, Sanda doesn’t completely use the same Taiji principles in applying, say a throwing technique. Each Chinese martial arts system (or any martial arts) has a distinct way of doing a technique. Some people might say, “Well, they’re all the same: a kick is just a kick and a punch is just a punch. It doesn’t matter because fighting is just fighting.” It’s not really that simple as there are clear yet often subtle distinctions in a way a certain martial arts system uses striking, grappling, and joint-locking techniques. Anyway, I like to use food analogies in martial arts. For example, a hambuger is just a beef patty between two pieces of bread, but most fast food junkies will tell you that a Big Mac and a Whopper are two very distinct hamburgers. There you go: Sanda and Taiji are under the blanket term of wushu, but I’d say both are different in many ways.