Correct use of Shovel for Digging

Is there a correct way to use a shovel to dig? Your back will tell you. I'm now talking about the long handled shovel in particular the Irish Digging Shovel. About this time of the year I get some hits on a post that I wrote in 2012:
irish digging shovel

I have scoured the internet to see if there was any instruction on youtube. There is and it will generally put you in the hands of the chiropractor. Only one man offers any sound practice that uses the length of the haft as a lever and your thighs as a fulcrum point. He learned this art from his father who was a pipe layer and his stance betrays the usages of that occupation – closed with a shorter grip that would be the best method in a tight trench. He crosses the shovel across both thighs in a more crouched position than I use in digging mode. It works and the principles are much the same as I learned when I was a labourer on a building site from a 70 year old Cavan man.
shovel like a boss

Here is a short clip of myself 'I mbun sluaiste':
digging

Notice the rhythm of the sway back that lifts the shovelful easily and that the digging foot and the lower hand are on the same side.