Swiss-style Pruning

I would like to hear about the methods involved in Swiss-style pruning. This valley in Washington had a high percentage of Swiss settlers consequently I see a lot of Swiss-style pruned apple trees.
From what I see, it appears that several branches from the trunk that are at a convenient height are bent in a bow shape so their tips point towards the ground. They then are heavily pruned, it seems by a modified form of pollarding.
So a mature tree will be pollarded one year and it will send up hundreds of water sprouts and look like a porcupine. The water sprouts are allowed to grow for a year and then they are thinned out leaving far fewer that will become fruiting branches close to the main arching (scaffold?) branches. These sprouts are allowed to produce fruit for several years and then the pollarding process is repeated (to renew fruiting wood?) Or, so it seems this is the process. These are just distant observations. What is the actual process and reasoning behind it? It seems quite productive, open to air circulation, and keeps the trees at a convenient picking height. I have never seen it in a large commercial orchard. It seems to take advantage of the higher fruit production that occurs on horizontal branches (compared to less production on vertical branches). Is there anyone knowledgeable and experienced with Swiss-style apple tree pruning out there that can explain it?