Harry spinning a K13 glider at the London Gliding Club 

Don't want to be critical, but this is the method of spin entry we generally taught until the early 1980's, but it is never the way that an inadvertent spin, the one that can harm you, happens. The deadly spins tend to happen with almost level attitude, but plenty of back stick, in a turn (low level thermalling, base to final turn, or a low turn off a cable break without waiting for speed to be established). I know of instances where a spin was not recognised because it had not been preceded by the entry as taught. In one of these, the pilot denied having been in a spin, and only recovered having given up and let go the controls, fortunately having started with plenty of height.

The good old ASK-13.

Very nice video. Great performance. Where did you strap the camera? I have an extreme camera but I don't know where to strap it in the glider

Approximately how much altitude will you lose in a spin on average?