It’s demanding work to get a rowing shell through the rigors of competition in the (hopefully) placid waters of a lake with no headwind to deal with. Yet for the two-person, four-person and eight-person rowing teams that become proficient at it, the synchronization of the team members with each stroke is a beautiful thing to watch. It’s almost hypnotic. The best teams from the Northwest — as well as standout individual rowers — will showcase their talents this weekend at the USRowing Northwest Masters Regional Championships at Dexter Lake Reservoir, put on by the Oregon Association of Rowers in Lowell. Watch men and women rowers from age 21 to their 80s carve the water with their oars, gaining speed as they race to the finish in heats and finals. Winners in each category qualify for the USRowing Masters National Championships in July in Oklahoma City, Oklahoma.