How Olympic Timing Works

As you're no doubt aware, the Olympic Games are held every two years, alternating between summer and winter athletic events. Because of the distinctions between these events -- from distance considerations to weather concerns -- the timing technology can vary greatly from sport to sport. Let's start with summer competitions.

Track/Athletics

In sprint races like the 100-meter dash, which can last less than 10 seconds, timing is of the essence. Therefore, every aspect of timekeeping is electronic, even the starting gun. And the starting "gun" is less pistol-like than ever, since security is understandably squeamish about weapons at Olympic events. Although it may look like a label maker, this starting gun is connected to speakers equidistant from every runner, to prevent a closer runner from hearing the starting gun even a millisecond before a runner farther from the gun. But no fear -- the sound still mimics a pistol [source: Lecher]. It's also integrated with the timing system to avoid discrepancies.

At the other end of the race, a laser is projected from one end of the finish line to the other, where a light sensor, also known as a photoelectric cell or electric eye, receives the beam. It works by having the two photo cells (set at different heights to avoid only recording an arm movement) aligned with the finish line. As a runner crosses the line, the beam is blocked, and the electric eye sends a signal to the timing console to record the runner's time.

One serious improvement to Olympic timing technology that's used in many events is the Scan'O'Vision camera. It records that "photo finish" we crave at a competitive Olympics. Unlike the old film camera, these use digital recording technology. They scan an image through a thin slit up to 2,000 times a second [source: Omega]. When the leading edge of each runner's torso crosses the line, the camera sends an electric signal to the timing console to record the time. The timing console sends the times to the judges' consoles and an electronic scoreboard. The images themselves are sent to a computer, which synchronizes them with the time clock and lays them side by side on a horizontal time scale, forming a complete image. The computer also draws a vertical cursor down the leading edge of each runner's torso at the time the finish line was crossed. This composite image can then be broadcast on a digital display within 15 seconds of the race's end to help make a decision on a close finish {source: Omega].

In longer races, such as the marathon, the clock also starts with an electric gun. However, the large number of competitors makes it impossible for all the runners to leave the starting line simultaneously, and dozens of runners can cross the finish line at a time. Because of these considerations, marathons require a more individual system of timing -- radio-frequency identification (RFID) tags.

Look at each runner's shoe and you'll see a small RFID transponder attached to it, sending out a unique radio frequency. Have you ever noticed the mat that stretches over the starting line at a marathon? It contains loops of copper wire that function as an antenna, picking up each runner's signal and sending the identification code and start time to the timing console. Mats track each runner's progress every 3.1 miles (5 kilometers), automatically displaying the best times on the scoreboard. Another mat sits at the finish line and records each runner's finish time. Officials then compare each competitor's time with the time clock, which is initiated by the starting gun.

Big marathons like Boston, New York City and Los Angeles also employ this technology, provided by companies such as Texas Instruments. It should be interesting to see whether the Olympic marathon or other suitable events ever adopt under the skin RFID technology or another sort of wearable.

Cycling

Because cycling events face timing challenges similar to that of marathons, the technology is much the same.

RFID tags, attached to each bicycle frame, emit an identification code to antennas placed at the starting line, finish line and along the road. These antennas register each rider's time and send it to the timing console for comparison. High-speed photo-finish cameras are set up at the finish line, including above the track, to provide a time-sequenced visual record of the winners, including a vertical cursor delineating the front edge of each rider's tire, to be used in case of a close finish.

Aquatics

Similar to the short-distance track events, each swimmer's starting block has an attached speaker to announce the activation of the clock by the timing official, or starter. In an event like the relay, the swimmer in the water must "tag" the next teammate by pressing on a touch plate located on the pool wall. The contact plates are made of thin stacks of polyvinyl chloride (PVC) and horizontal strips that register focused pressure (as from a swimmer's hand) but not dispersed pressure (as from waves in the pool). As little as 3.3 pounds (1.5 kilograms) of force is needed to activate the pad; a wave might register as 2.2 pounds (1 kilogram) [source: Park]. When the pad is activated, a signal is sent to the timing computer to record the first swimmer's time, denote the start of the second swimmer's time and report the time to the scoreboard.

The process works the same for the individual events such as breaststroke, freestyle and backstroke, during which the swimmer registers his or her time by pressing on the contact plate at the end of the run. Aquatics also use photo-finish technology similar to track events, recording an image of the finish at 100 frames per second. (That was the camera that came in so handy in Michael Phelps' 2008 win.).

Another technology that debuted during the 2012 London Olympics was the Open Water Gate for the swimming marathon. (Aren't you tired just thinking about it?) Previously, times were just given at the start and stop of the race. But now swimmers wear wrist transponders that respond to gates along the racecourse, giving times and measurements as the marathon occurs. There's also the photo-finish technology at the end of the race, so judges can determine a winner when a transponder gives times too close to call [source: Swatch].

Sledding

Because Olympic sledding competitors travel at speeds up to 90 miles per hour (145 kilometers per hour), they win by some of the narrowest margins. When accuracy to the thousandth of a second or better is key, and timing equipment has to withstand temperatures as low as negative 30 degrees Fahrenheit (negative 34 degrees C), special technology is required.

The track is equipped with multiple infrared emitters and receivers, which send the time to a central computer each time a beam is broken. Laser technology, while effective in the track environment, was replaced by infrared beams for the 2002 Olympics in Salt Lake City after research revealed that falling snow often tripped the laser beam and frost clouded the electric eye, reducing accuracy.

Speed Skating

The timing technology for speed skating got a technological boost for the 2014 Sochi Olympics. Skaters wear lightweight transponders on their legs that can record their times and rankings in real time during the race [source: Omega]. The clock is triggered by the starting gun that first appeared in the Vancouver 2010 Games, and the tip of the athlete's skate will trip the photo cells to stop the time. But because speed skaters reach speeds up to 30 miles per hour (48 kph), and a skater can win by as little as the tip of a boot, two slit video cameras scan the finish line, time-stamping each image at 2,000 frames per second and sending the complete image to the judges to help determine the winners in case of a photo finish [source: The Olympic Games].

Skiing

Downhill skiing competitors begin their races at starting gates, with Snowgate starting gates introduced in Vancouver. The gate has a wand or bar that only emits a starting pulse when it's at an equal angle for every skier. The timing starts the second they burst through the bar, which allows them a little leeway for their initial push [source: Omega]. As with the sledding events, an infrared beam is tripped at the finish line to stop the clock.

For the long-distance skiing events, such as cross-country and Nordic, RFID tags attached to each skier's boot send individual signals to antennas buried beneath the snow at the starting line, finish line and points in between. In this way, a skier's starting time, finishing time and progress are all tracked, recorded and broadcast, taking any time penalties into consideration. GPS satellites are also used for the Nordic competitions to measure distances between competitors throughout the race.

Although many times are only published to the hundredth of a second, Olympic timing standards require that timekeeping be accurate to the millisecond. With such a small margin of error, timekeepers must plan for the worst. Twenty-first century technology, however, can give a time that's way more accurate than a millisecond.

Quantum Timer and Aquatic Quantum Timer -- Introduced during the 2012 London Olympic Games, the Quantum Timer increased the resolution of recorded time to one-millionth of a second, which is 100 times more accurate than the previous technology. It also showcases a precision of 0.1 parts per million. The precision measures the repeated reliability of the measurement, so this means that there is a maximum leeway of 1 second per 10 million seconds. In other words: It has to be not just accurate, but accurate every time. Another cool part of the Quantum Timers is that they have 16 independent clocks, so each runner or swimmer in a race can have information simultaneously shown on scoreboards or television screens.

False-start fail-safes -- Because many athletes "jump the gun," timekeepers must also be referees of a sort to preserve the accuracy of competitors' scores. Scientists have measured that an average human takes one-tenth of a second to react to a stimulus, such as the starting gun. In the Olympics, the clock stops if an athlete starts sooner than a tenth of a second after the signal is given, because this means he or she began to "react" before the gun was fired.

Often, the competitor who started prematurely is disqualified. In aquatic relay events, reaction time is analyzed not only at the start of the race but also as each swimmer "tags" his or her teammate (in this case, the touch pad). Scientists figured out it takes 27/1000 of a second for a foot to peel off the blocks. They decided that any start less than 0.04 seconds after a teammate tags the wall is a false start [source: Park].

In addition, the starting blocks used in both track and swimming events have electronic pressure plates. Introduced in London 2012, these blocks contained a significant advancement: They no longer use movement to measure a runner's false start. They now measure force against the block, which is supposedly more accurate [source: Swatch Group].

Because the official Olympic timekeeper provides heavily redundant systems and multiple timing devices with both numerical and visual data, timing disputes are usually resolved quickly by analysis. However, when a valid complaint is made, this almost always leads to research and advancement of the existing timing technology. For instance, after Silke Kraushaar's gold-medal luge win in 1998, it was discovered that the photoelectric sensors had a margin of error of exactly two milliseconds -- the span of time Kraushaar won by. In response to concerns about the system's accuracy, then-U.S. Olympic Committee Principal Engineer Tom Westenburg developed the high-modulation, triply-redundant system in current use, which is accurate to less than half a millisecond [source: Leo].

Although the history of the Olympic Games stretches back as far as 776 B.C.E., the history of Olympic timing technology began just over 100 years ago. These are the major breakthroughs:

For more information on Olympic timing technology and related topics, check out the links on the next page.