A motorcycle racer I follow on Twitter just used this term, which I'd never heard before, and a quick google didn't help.

I'm assuming that what he means is training targeted to lose muscle mass without losing fitness. A lot of riders have been doing that in the past 3-4 years as they've discovered the limit where the detriments of weight outweigh the benefits of strength, and/or switched classes to a lighter more flickable bike.

I'm guessing that this may be particular to motorsports, but maybe there are other sports where the weight of the equipment and the G-forces involved vary enough from discipline to discipline, and as technology develops, that this might be a question.

Anyway, I'm curious as to what such training involves. Anyone?