Sybase Open Ball Speed (Page 4)

The Groundstrokes

Our analysis of the returns showed that an average the ball had slowed to about 20mph before the opponent's hit. This was in fact almost exactly the same speed the ball was traveling before the hit on Sampras's groundstrokes, an average of 19mph.

Our data showed that 9 Pete Sampras forehands had an average initial velocity of 76mph, with the fastest being 82mph. On the backhand, we measured 2 Sampras hits that averaged 69mph. This equaled an average increase of over 50mph in the speed of the groundstrokes after the hit, compared to the incoming speed.

Other than the serve and the overhead, the biggest change in velocity after a hit occurred when the ball was struck off the ground on the forehand and backhand.

The pattern of deceleration on the groundstrokes closely matched that of the serve and return. The friction from the air and from the bounce on the court reduced the speed by over half. At the end of the flight this speed reduction totaled almost 60%. On average Sampras's groundstrokes started at about 70-75mph and finished at about 30mph.

Sampras Forehand:

Number of Forehand	Pre-Hit Speed	Max MPH After Hit	Pre-Bounce MPH	Post Bounce MPH	End MPH
9	19 MPH	76 MPH	49 MPH	34 MPH	31 MPH
Speed Change	---	+57 MPH	-27 MPH	-15 MPH	-3 MPH
Cumulative Speed Change (From Max After Hit)	---	---	-35%	-55%	-59%

Sampras Backhand:

Number of Backhand Returns	Pre-Hit Speed	Max MPH After Hit	Pre-Bounce MPH	Post Bounce MPH	End MPH
2	17 MPH	69 MPH	49 MPH	32 MPH	28 MPH
Speed Change	---	+52 MPH	-20 MPH	-17 MPH	-4 MPH
Cumulative Speed Change (From Max After Hit)	---	---	-29%	-54%	-59%