I tensed up and tucked slightly, protecting my neck and head from any damage. The student's weight instead came down directly on my right shoulder as I landed, pinning me to the mat and crushing my shoulder between judoka and floor.

There was a jolt of intense pain, and something inside my shoulder made what can best be described as a "squirting" sound... similar to the noise it makes when you tear a drumstick off a well-done turkey, but quite a bit wetter sounding.

The pain dissipated almost instantly, being supplanted immediately by a hot sensation. It felt like someone had injected a syringe full of hot tap water directly into the muscles around my shoulder blade.

The heat was also gone almost instantly, this time replaced by an utter numbness, spreading down from my shoulder to my arm, and then settling into the fingers.

It was one of those injuries where you know - you just know - that you will feel it the next day... and the next month... and probably on cold, rainy days twenty years down the line.