I get some strange looks when I do my neck exercises in front of BJJ and especially Muay Thai folks. It looks strange to see someone apparently running around on their head, but there a solid method and extremely sound reasoning behind this activity.
Leo Frincu is a former wrestling world champion, successful entrepreneur, and has been strength and conditioning coach to champions like Ronda Rousey, Diana Prazak and Romulo Barral. In the video above, he demonstrates the carousel, and some regressions of the front-to-back bridging sequence.
I started looking for effective neck exercises while trying to return to training after spraining my cervical spine during BJJ training in 2011. Previously, my neck had been strengthened through the process of Muay Thai clinching, which had given me very strong and active upper trapezius and levator scapulae muscles, but had not prepared me at all for the myriad of positions in which one finds oneself while grappling – falling or being dropped on the mats head-first, posting and bridging on the head, being stacked, and resisting chokes and neck cranks (intentional or otherwise.)