[RickM]

You don't need to be Charles Atlas to operate a pole saw. First the majority of the weight is at the base of the pole, not at the head.

Second, when using the shoulder strap your shoulder is more or less the fulcrum (ala 1st class lever) and you use more balance than strength to operate.

Lastly, pole chainsaws are meant to rest on the branch they're cutting. Most also have "teeth" at the base of the blade so if there's any kick the saw stays put and continues cutting.