In reply to mypyrex:
Not sure about using more energy whilst using poles, however I found that on steep uphills whilst carrying a load I can maintain a longer stride when using poles rather than taking smaller strides without using poles.
On the Miners Path there was probably good traction too. Poles are really helpful to maintain a good stride on either loose or slippery ground but I find they are of little use on easy terrain.
For me Poles come into their own in descent (though this is not what you are posting about).