Picking with an Arched Wrist

From The Ultimate Chops Builder: 51 Exercises to Give You Killer Technique:

“The truth is, you need to practice everything using the fast picking style that your body naturally favors — that is, the exact movements you use to pick super fast on a single string. For most players, this involves picking from the wrist (in some cases, with the wrist arched in “quick strumming” position, where the pick hand’s pinkie or heel is used for stability), with no ‘stiff­ arming’ and, again, no fingertip-based movement.”

I would like to omit “in some cases” from the text above. An arched wrist, like the one in the picture below from a mandolin course in the Swedish magazine Levin-bladet, will result in a natural swing in your hand. It doesn’t have to be such a pronounced arch, the important thing is that you feel that swing.