Tennis Industry magazine


Removing the Tennis Court’s Last Variable?

By Peter Francesconi

When it comes to the tennis court, everything is standardized and consistent — except in one area: net tension. While there are recommended tension ranges, there never has been an effective, easy way to measure the tension of the net, and that’s important when a ball strikes the net cord. If a tournament’s net tensions are all over the map, players will have no idea from court to court how a ball may react.

For facilities, too, it’s a practical matter. If the net cable is pulled too tightly, it can ruin the net, net posts and footings, causing cracks in the courts and causing the net posts to lean in — repairs that can cost thousands of dollars and result in down court time.

Now, though, David Glass (above) of Knoxville, Tenn., may have hit on an affordable solution to the inconsistent net-tension problem. Glass is the CEO of Cable Tension LLC and has invented the TNT Gauge (which stands for “Tennis Netcord Tension”), a device that installs on the anchor hook on the outside of a net post and measures the tension of the net.

“We believe we are removing the last variable from the tennis court,” says Glass. “The TNT Gauge is proving to be the first inexpensive, practical and user-friendly method of measuring net-cord tension before and during play, an especially useful factor when the rules include playing all lets.”

Glass obtained a patent for the TNT Gauge in November 2010, and so far he has been adding to a list of impressive credentials. In fact, after testing the TNT Gauge on two outer competition courts at the 2011 US Open, the USTA has decided to buy 18 more, equipping all 20 competition courts at the 2012 Open with the device.

The TNT Gauge also was used at five 2011 US Open Series events, including on all eight competition and eight practice courts at the Linder Family Tennis Center in Cincinnati, home of the combined men’s and women’s Western + Southern Open. It was also used at the Winston-Salem, Los Angeles, Atlanta and New Haven events.

During the 2011 season, World TeamTennis used the TNT Gauge in four cities, and it’s been used at NCAA regionals in Knoxville and for Division 1 dual matches. In addition, the gauge has been installed at the Malaysian Open in Kuala Lumpur, a men’s pro tour event, and is being evaluated at Asian and European ATP events.

Glass says the TNT Gauge was developed in cooperation with the University of Tennessee’s tennis program in early 2011 and is on all 12 courts at the university. “Tennessee has been fortunate to use the TNT Gauge all season,” said Vols’ Head Coach Sam Winterbotham. “I believe it is the first time we have been able to say confidently that the nets are all the same tension. In men’s tennis we play let cords, so knowing that the bounce off the net will be uniform really helps. It is a fantastic product.”

“Studies by the USTA and International Tennis Federation suggest that 400 to 550 pounds of tension is a good playable range,” says Glass. The TNT Gauge has a green-colored area on the unit that covers that range. “It’s not dictating a tension; it’s a tool to let officials set the tension.”

Glass, a longtime recreational 4.0 player who has an engineering degree from the University of Tennessee, says, “I was always the guy who had the crescent wrench in my bag. I just couldn’t stand loose nets.”

The TNT Gauge ( is manufactured in Knoxville and available with club or team logos imprinted. There are two models, which ensure compatibility with all net posts with external anchors. Price for seven or more units is $139 each, but contact Glass for details at or 865-307-0474. “We’re trying to make it fit club and school budgets too, not just pro events,” he says.

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About the Author

Peter Francesconi is editorial director of Tennis Industry magazine.



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