Three mile leg

While we were on holiday in Thailand, J strained her knee jumping out of a boat, and being a loyal husband, I ended up massaging it using some of the Tiger Balm red ointment we'd picked up en route to stop it stiffening up

The red version contains cinnamon oil and has a distinctive smell. Anyway, during one of these massage episodes J told me an intriguing story she'd been told by her acupuncturist - who had trained in China.

During the Long March, when the Red forces had been slogging across the grasslands of Xianjiang, people would lie down and give up, due to sheer exhaustion and lack of food. And the story goes, one of the doctors cooked up this tingling balm, that when rubbed on the exhausted person's legs would mean that they could march another three miles and finish the day's march.

Obviously there was an element of psychology in this, but given that every asian grocer has various medicines and nostrums like this (for example the unfortunately named Vietnamese 'Family Rubbing Compound'), it all seemed likely.

So I expected to be able to Google for 'three mile leg' and come up with pages and pages about it. But googling doesn't bring up anything at all.

Is 'Three mile leg' a myth - or has it simply not made it into English language accounts of the Long March ?