New Dive Platform Aimed At Shaving Vital Microseconds In Competition

February 17, 1998

GAINESVILLE — The start looks perfect, but the coach isn’t pleased.

Eyeballing an electronic monitor, Kevin Thornton, University of Florida women’s swim coach, sees the swimmer reacted sluggishly to the starting horn. The screen also indicates she jumped too high, wasting valuable microseconds in the air. He tells her to try again.

Such a scenario is likely to become common during practices next fall, when Thornton begins using a “smart” dive platform being developed by a UF engineer who is also an avid recreational swimmer.

Civil engineering Professor Dave Bloomquist’s platform is designed to serve as a training tool for swimmers by measuring how quickly and efficiently they start, among other things.

“We will not only be able to get them quicker off the starting platform and more efficiently off the starting platform, but we’ll also be able to test the kids periodically throughout the season to find out how tired they are,” said Thornton, who will be in the spotlight this week as he coaches UF’s team in the Southeastern Conference championships at the Stephen C. O’Connell Center.

The plastic-and-metal platform looks low-tech, but a closer inspection reveals a cable snaking away from an electronic device mounted underneath.

When a swimmer pushes off, steel rods on ball bearings transfer her effort to a load cell, a device that measures force. The cell sends a signal to an oscilloscope that displays it as a wavy line similar to the one created by a heart-monitoring machine. A comparison of the plot with another line that tracks the horn reveals her reaction time. The oscilloscope also registers how long the swimmer spends on the platform and how hard she pushes.

Tests during practices at the O’Connell Center early last spring revealed swimmers

reacted to the horn in about one-fifth of a second. That may seem insignificant, but as world-class swimmers push the performance envelope, even smaller blocks of time can separate winners from losers. At the 1992 Olympics, a swimmer won the gold in the 100-meter butterfly after finishing one-eighth of a second faster than the runner-up.

“In swimming, a start can be very important,” Thornton said.

While swimmers may know instinctively if they dive poorly, Thornton will be able to use the device to set performance goals.

“He knows who is fast, who is slow, and maybe he can help a person’s technique or concentration,” Bloomquist said.

Last spring’s test runs proved the device would be useful, swimmers said.

“If the coach says you have a slow start, you don’t really know how to change it,’ said Karie Bullock, a 19-year-old UF sophomore. “I thought the platform really helped because it told you both your reaction time and the power you got off, which are the key elements to a good start.’

Competitive swimmers start from a crouched position, their hands pushing off the edge of the platform. Bloomquist’s latest design takes separate measurements of how hard swimmers push forward and skyward with their left and right hands and legs, respectively. That will give Thornton a more detailed picture of their performance than visible to the naked eye, revealing if a swimmer relies more on her right leg than her left, for example.

“We’ll be able to adjust how they produce the force on the block to make them dive more efficiently,” Thornton said.

Jason Brawley, a recent engineering graduate, helped build the first device. Student C.J. Baier is assisting on the latest one.

The platform is only one of several swimming performance devices being designed by Bloomquist, who swims more than a mile a day in the O’Connell Center pool. Others include an underwater digital display that will tell swimmers how many laps they’ve completed in practices, even if there are many swimmers in the pool. The device works by receiving signals from tiny waterproof transmitters worn by swimmers.