Who Times World Records at the Olympics?

This August billions of viewers will watch the Olympics. Two of the most popular sports, swimming and track are timed. Not only are medal winners are determined by the clock, but performances are compared with previous records.

If a new Olympic or world record is set there is extra excitement. A world record documents the best performance of that particular feat throughout history. The athlete can bask in the fact that for the moment at least he or she can do something better than anyone else on earth now and anyone who lived before!

But who are the timers behind such significant achievements and certifies accuracy? It is generally taken for granted that the record times are correct. In fact, the days of officials clicking a manual stopwatch have been superseded by $100,000 systems, double and triple backups and integrated real time displays and data processing.

Two of the most popular sports in the Summer Olympics involve precision timing: Swimming and Track. The technology and complexity of timing systems of these two sports illustrate the efforts made to ensure reliable, accurate timing.

Swimming - Touchpads are Key

At the 1968 Mexico City Olympics, Omega of Switzerland introduced the touchpad and automatic timing where the swimmers' touch at the pool wall triggered a signal for lap and finish times. Suddenly, the impossible task of judging exactly when a swimmer's fingers touched the pool wall amidst thrashing water and spray was automatically sensed to an accuracy of 1/1000^th of a second and a precision of 1/10,000^th of a second. This meant the actual elapsed time from start to finish could be determined to 1/1000^th second, but even if two swimmers tied to the same 1/1000^th of a second, the system could tell who won, to at least another decimal point or more. However, official rules only allow recording to 1/100^th of a second because variations in the dimensions of a pool could affect more precision.

The touchpad consists of sheets of rigid plastic behind which are strips of sensitive contact switches. The sensitivity is set to trigger with the swimmers' push but not to wave action. The touchpads spanned the entire width of the lane and are 90 cm high - 30 cm above water line and 60 cm below.

The touchpads not only sense a swimmer's finish time accurately but also registers accurate split times of every lap. This compelled the swimmers to touch the side of the pool on every turn, eliminating the chance of a flip turn short of the wall without a proper touch.

In actual operation, there are challenges. In early systems, the operator at the timing console had to manually arm, disarm and reset the touchpads throughout the races. For example, when relay members finished and were recovering in the pool the touchpad had to be disarmed. Otherwise, during climb out of the swimmer, a live touchpad would register an extraneous time.

As soon as the first swimmer was out of the pool, the touchpad had to be re-armed for the split time of the next swimmer who might be arriving just as the teammate climbed out. In other words, the operator had to be watching the pool and activating just in time and not too soon. Now imagine operating the console with swimmers in eight lanes, relay teams exchanging at different times, dozens of teammates jumping up and down, officials blocking the view of the touchpads, and spectators going crazy with screaming and stomping! Keeping a cool head in such an environment was extremely difficult. One mistake and a split time might be missed or, worse yet, a final time missed! You did not want to be the operator that missed a world record!

The latest systems are still not fool-proof but allow arming delays to be pre-entered for every event at any level of competition. The touchpads are automatically armed only during the narrow window of time when swimmers of that meet for that event are expected to touch. This does not mean, however, that usual circumstances won't occur, such as swimmers touching an adjacent lane's touchpad on climbing out.

Also updated for the Olympics and other high-level swim championships is the backup system. In most swim meets, three timing officials are assigned to each lane. They start their stopwatches when they hear the starting horn, then at the finish they peer into the splashing water to catch the moment of truth. The update mentioned consists of a separate timer with an octopus of cables leading to the officials, each of whom have a button to push instead of a stopwatch. Obviously this contributes nothing to the detection of the moment of touch but there are some advantages. First, the reaction time error at the start is eliminated as the officials need not manually trigger the start time - this is automatically synchronized in the timer to the actual start. Secondly, the system automatically handles administrative chores, such as selecting the middle time of three officials, or if only two officials, the average of the two times. Additionally, major meets like the Olympics also have high speed video cameras overhead at every one or two lanes to record images of the swimmers.

Too detailed for this article are the elaborate fail-safe features in modern systems, including completely independent dual channel timers and isolated power sources. Not surprisingly, the operation of the Olympic timing systems, which in the Beijing Olympics will be by Swiss Timing, is conducted by highly trained electronic engineers, most of whom work year round on electronic sports timing.

Track - Catching the Crossing of a Torso

In track events, it is a completely different world. Despite all the technology that has contributed to automatic timing of sports, there is yet no fully automated way to determine exactly when the first part of a runner's torso crosses the finish line.

The only solution has been based on the concept of a photo finish camera. This is a camera that only sees a narrow strip of space at the finish line. For decades, such a camera involved moving a continuous strip of film across an open slit in the camera and recording whatever it saw go by at a set speed. Thus, the film captured images of a runner's torso as it crossed the finish line. The elapsed time was also recorded on the film precisely as it passed the slit so the image of a torso could be matched to the time shown along the bottom of the film.

Since 2000, the film photo finish camera was replaced by a digital version. Normal video cameras shooting at approximately 30 frames per second would not suffice since runners could change places between frames. Special digital photo finish cameras used at the Beijing Olympics will shoot at 1000 to 2000 "frames" per second, each frame being only a vertical strip of an image at the finish line. So that all torsos in every lane will be visible, the photo finish camera is positioned high at one end of the finish line looking down on the competitors at approximately a 45° angle.

After each race, the photo finish picture is viewed by officials who declare the winners and times. Although the photo finish camera greatly facilitates judging and timing of track events, there are occasions, especially in sprints, where portions of two torsos touch the finish line together and human judges must decide.

Photo finish pictures often show the limbs of runners either shrunken or bloated in width, or even an elongated foot that looks three feet in length. These are not distortions. Remembering that the images are collected over time as they crossed the finish line, these apparent distortions are correct records of time that the limb crossed the finish line. The speed of the recording (on film or video) is set for the average speed of the runner so that the final image is recognizable. An arm that is swinging forward just as it crosses the line is going faster that the average speed, so appears in the slit of space for less time than average; thus it looks thin. Conversely, the arm just swinging back at the finish line will look fat. The elongated foot shows it landed exactly on the line, thereby being stopped for a short moment while time is still going on. How long it remained on the finish line can be determined by the time scale at the bottom of the picture.
These timing systems in swimming and track are examples of sophisticated sensors and systems used in the primary timing of other sports. However, the systems also include much that is beyond the scope of this article. Examples: combinations of human and video backup, detection of false starts, provisions for backups and automatic feeds to scoreboards and TV.