In some internal arts, such as aikijujutsu, nami "waves" are used in varying degrees of amplitude and frequency to disassemble an opponent's structure and to shock the system. The center of gravity/mass is the target, and it is accessed through the person's joints from the point of contact, through the spine.
Here's a clip assembled from some classes taught by Salahuddin Muhammad (generational head of Hontai Hakkei Ryu Aikijujutsu). He is applying nami in "slo-mo" and with larger-than-normal movements so that they are visible and you can observe the process. If he were delivering them more quickly and with smaller movement, the effect would look (and feel) very "shocky," like a quick pulse of force. The waves would still be there, just much harder to see, and the recipient would not feel them -- only a jolt that takes apart his equilibrium and structure, and feels like an "electric shock." This is a form of kuzushi-on-contact.