Bees don't always balance their hives well and put all the weight at one end.
If you pick it up with the heavy end towards you its not too bad but if not it
can be awkward.  Central handles force you to lean forward when lifting
putting extra strain on the spine.  Try offsetting the grips so that on your
weak side the handle is about one third of the way along the hive body and on
your strong side, two thirds.  I find this much more comfortable than
equidistant grips and you may do so too.
Chris Slade