The biathlon is a test of cross country skiing endurance and shooting skill. The two skills cross paths when a heavy-breathing skier needs to shoot a tiny target 50 meters away. Shooting cadence - the way shooters approach the target and how well they stay on the target with the rifles recoil - determines how well they shoot.
To track the cadence, Tim Conrad, principal engineer at the US Olympic Training Center in Colorado Springs, Colo., designed an IR laser and camera combination to videotape an athlete's shooting performance. The system consists of a small infrared laser from Micro Laser Systems of Garden Grove, Calif., that is mounted beneath the barrel of a rifle.
|A photonic system monitors the shooting performance of an athlete training for the biathlon. Shooting cadence can be seen on a monitor (inset) and videotaped for review.|
The laser beam is sighted as a rifle scope would be: The beam illuminates the bullet's impact point on the target. However, because the laser operates at 830 nm, it is invisible to shooters and does not affect their performance. Conrad said he was pleased that Micro Laser was able to create a 10-mm round spot at 50 meters with the IR laser.
An IR camera near the targets captures the shooting performance on videotape, which is reviewed by the coach and the athlete after a training session. In addition to the laser, the system integrates a trigger sensor and a heart rate sensor so that the coaches and athletes have a more complete idea of the entire shooting performance.
The athletes do not actually ski with their own rifle, because it has the laser device attached to it. They ski with a rifle similar in size and weight. When they reach the shooting station, they exchange the skiing rifle for their own. Conrad said that using the athlete's own weapons allows the training regimen to approximate competition shooting. "The laser weighs less than 150 grams," he said. "It does not affect the rifle's balance or feel."
Skiing would subject the laser to unnecessary bumps and jars. "The alignment accuracy [of the laser] is very critical," Conrad said. "The sensors and laser are lightweight and fairly fragile. Safety is also an issue. Even though it is less than 1 mW, we don't want the laser pointed at anything other than the target."
"The key to the effective use of sports science," he said, "is to determine the important aspects of performance, make an integrated package and write software to collect the data and display it in a quick and easy-to-use format. We give coaches information so they can do a better job of coaching."- Kevin Robinson