  This paper summarizes two previously published technical papers describing
what can be learned from measuring the motion of the golf club using two
accelerometers. The sensors are mounted at different points along the shaft of
the golf club, both sensitive to acceleration along the axis of the shaft. Two
distinct signals are resolved. The first signal scales as club speed, which can
be used to understand details of tempo, rhythm, and timing. The second measures
the acceleration of the hands, which reveals the torques that generate power in
the golf swing. A comparative study of twenty-five golfers shows that club
speed is generated in the downswing as a two step process. The first phase
starts at the top of the swing and involves impulsive acceleration of the hands
and club. This is followed by a second phase, the release, where the club is
accelerated while the hands decelerate.
