Luo Yang hadn't expected that ordinary people would find doing the splits so strenuous.
If Qiao Zai Shui weren't learning martial arts, Luo Yang wouldn't have pushed her to do so.
Qiao Zai Shui's physical fitness was originally poor, and if her flexibility wasn't sufficient, then it would take at least a year of hard training before she could think about defeating one or two strong men.
Based on Qiao Zai Shui's own conditions, Luo Yang first helped her train enough flexibility, and then he would instruct her in self-defense techniques.
Physical training needed to accumulate over time to be effective; it was not something that could be achieved overnight.
Moves are fixed, but being adaptable is what makes a master.
Luo Yang could guarantee that Qiao Zai Shui would become an average master, but whether she could become a top-tier master depended on her natural talent and fortune.
If one wants to learn real kung fu, they have to put in the hard work.