LMC stands for Loss Of Motor Control and it occurs due to hypoxia. It is extremely dangerous in the water and can prove to be lethal, if the diver is alone. When the brain is badly starved for of oxygen it will shut down and the freediver will not be able to move properly and will struggle to reach the surface.
Alchemy spearo Robert John recently went on a doggie hunt in Guam and unfortunately had an LMC. His GoPro recorded the whole incident but thankfully his buddy was there to help him out. Watch On IGTV!