Nordic Walking

Is there any walkers out there that could explain the difference between these poles. What I found out was – I don't honestly think there is a difference. I have been mountaineering and hillwalking for decades but never seen a 'nordic' pole that doesn't look like a simple telescopic walking stick with a wrist strap. Some people use walking poles because apparently they can help burn 20-40% more calories. The only difference I have ever seen is a few of the 'nordic' poles have a velcro type wrist strap on the handle as a support. Walking poles just seem to have the simple loop. All I can help with sorry.