why is his back hand straight? i was always told to keep it at 90degrees, but i know it is a great relfex when you put it back like that
would doing this increase my start?
well 90 degrees would be more for the rest of the sprint where leg turn over happens too fast to use any kind of arm motion like he's doing here.. so it's mostly for coming out of the blocks, since alot of strength is required to come out of the blocks, that extra elbow + shoulder extension helps more forcefully extend the opposite leg.. try it out, just use it on the first step, see how it feels, it should give you more pop coming out of the blocks IMO.
peace
