I can see how lots of back-peddling would be such a strengthener there; if you do it enough (like in daft backwards races and such for fun in training - I was/am a nippy runner, and used to take the piss like that when significantly ahead on longish runs), the hammies are where you seem to feel it working most, you can sense them stretch more as you 'stride'. Never really gave much thought to how seriously beneficial that could be, though!
Would it not just be enough to include that significantly more itself in regular training for our quickies though? Or in the gym? How about backwards peddling on bikes on some low-but-noticable resistance setting? Is it simply more natural and beneficial when implemented in a 'touch footy' match context, with the regular changes of running direction (I presume, I've never even heard of it!) and proper competitive game element keeping it from getting boring, like the players are so involved in trying to win they don't even realise they're training that particular part so hard (similar to how little 1 & 2 touch match sessions really seem to improve you over time without you even knowing, 'cause you're all just having fun)? Just curious.