I — THE RATIO IS REAL
Frame-by-frame video of tour professionals — from Hogan to Nicklaus to Woods — shows elite swings share an elapsed-time signature: the backswing takes about three times as long as the downswing. Measured on 30 fps video, one of the canonical tour tempos is 24 frames back, 8 frames down.
JOHN NOVOSEL, TOUR TEMPO (DOUBLEDAY, 2004). A YALE PHYSICS STUDY (GROBER & CHOLEWICKI, 2006) FOUND THE SAME ~3:1 AVERAGE WITH CLUB SENSORS.