According to The Bud Collins History of Tennis, Andy Roddick belted a 155 mph serve at Vladmir Voltchkov during the 2004 Davis Cup semi-final. Curious about your own serve? The answer is a download away.
Speedhero, is a new mobile app that turns your mobile phone into a sports radar. Share your results on Facebook or on the Speedhero site for a little competitive fun.
Select your distance (39 feet -- the distance from the baseline to the net), place the mobile phone within range and you're ready to start speed shooting. You will need to serve against a wall or curtain in order to generate the impact sound. Mark the height of the net on the wall with tape. Our tester John recorded a high of 128 mph.
Speedhero uses algorithms and your phone's microphone to detect the impact sounds of your contact with the ball and the ball's impact on a wall/curtain. Using a sport specific flight time dynamic formula, the app instantly calculates your top speed. Because the impact sound comes from the wall and not the court/service box, spin is not taken into consideration. A very cheap and pretty fun alternative to a pricey gun.
Cost: $8.80 USD. Visit Speedhero for more info.