The official name of the gesture is "Li Ning Heroic（winner） Gesture", simply symbolizing winning, which was how it was called when Li Ning Company first unveiled it. But later on the CEO of the company added the "L for Love" meaning- sounds a bit far-fetched to me though.
Actually all the WAG team members have their own way to do the gesture, here are how Sui Lu and Huang Qiushuang do it.
Sui Lu, He Kexin, Jiang Yuyuan and Yang Yiling are in the following photo. Can you tell who is who? All I can tell which one is Sui Lu.