I'll disagree slightly with posters who say that your arms should be straight 180 degrees at the bottom of the movement, since you want to keep your shoulders e

I'll disagree slightly with posters who say that your arms should be straight 180 degrees at the bottom of the movement, since you want to keep your shoulders engaged throughout; a slight bend through the elbow is best, I think. But by slight I mean 170 degrees or something, not 80 or whatever this guy is doing.