Even if you only practice a stand up art, primitive movements are still important to practice as part of you conditioning routine since they are those that mimic the process we all under went as babies. Rolling over, pushing up, crawling and then standing.

Here is the famous Steve Cotter (also of the Tang Shou Dao lineage) doing the "fuhugong" 伏虎功是 (lying tiger exercises). As I understand it, Xu, Hong-Ji took these movements from Judo and added them into the TSD curriculum.