From manual stopwatches to laser sensors: the technological evolution of time measurement in sport

From manual stopwatches to laser sensors: the technological evolution of time measurement in sport

The arrival at the photo finish of an athletics competition. Credit: Alvin Loke via Wikimedia Commons

When we watch a sporting event on television, such as i 100 meters flat of athletics, everything seems simple to us: the judge’s shot starts the race, the athletes run and at the finish line the final ranking with the times recorded by each participant. What we don’t see, however, is the technology that makes all this possible: sensors, lasers, photocells and super-computers who measure time with one infallible precision and provide us with real-time data and statistics.

From the bicycle timekeeper who chased marathon runners in the early 1900s to today’s artificial intelligence, the measurement of time in the world of sport, through glaring errorsbrilliant inventions and controversieshas undergone an extraordinary evolution towards search for perfectionwhich today allows us to understand in a more in-depth way the greatness of the most incredible sporting performances.

The first methods of measuring time in sports: manual stopwatches

THE’evolution of sports timekeeping it starts from afar, when it became necessary not only to determine the winner of a race, but also to know the time taken by an athlete to cover a certain distance. From the first modern Olympics in the late nineteenth century until the 1930s, timekeepers used manual mechanical watches to record times, reacting to start and finish signals with your human reflexes to start and stop the stopwatch. Considering that the human reaction time is 1-2 tenths of a second, one was enough blink of an eye or a slight distraction of the timekeeper to have macroscopic differences on the final time assigned to the athletes.

Furthermore, the precision of the stopwatch was limited to a fifth of a second, so in a 100 meter race two athletes credited with the same time at the finish line could have been about 2 meters apart from each other. To reduce these errors, we came to use up to three timekeepers for each athletetaking the recorded intermediate time as official. But even so, the human element remained the system’s Achilles’ heel.

The photo finish revolution

The 1932 Los Angeles Olympics represented a first significant revolution in the world of sports timing thanks to the introduction of the “Photo-electric Camera”, a “two-eyed camera” capable of recording up to 128 images per second. In that edition, US athletes Eddie Tolan and Ralph Metcalfe crossed the finish line of the Olympic 100 meters at the same instantbut for the first time in history the decision on awarding the victory was not made by human judges: photographic analysis determined that Tolan’s back was slightly ahead of Metcalfe’s.

At the same time, the “broken thread” method to detect times without the aid of manual chronometers. With this method the athlete, simply by running, “broke” a thread during the start and finish phases. This wire dropped a weight that opened (at the start) and closed (at the finish) an electrical circuit that activated and stopped a chronometer. Thanks to these two technologies, for the first time the judges no longer had a way to influence, with their reflexes, the times recorded by the athletes, and the photo finish concept that we know today.

Precise photocells and displacement sensors in sports

As the years went by, electronically measured times were incorporated into all types of competitions. Some disciplines began to decide their winners based on thousandths of a secondand the photocells they became the standard in sports timekeeping.

However, increasingly precise technologies were starting to reserve surprises And paradoxes. In 1972, at the Munich Olympics, a situation occurred in the 400 m medley swimming event that put the system in crisis: the Swede Gunnar Larsson and the American Tim McKee touched the finish line with same time to the cent4’31”98, but the measurement awarded the victory to Larsson by solo two thousandths. The judges awarded the gold to the Swede, but the decision sparked a debate: two thousandths of a second corresponded to less than 4 millimeters covered by the athlete at the average swimming speed, a distance lower than the construction tolerance of the Olympic pools. The world swimming federation therefore decided that, from that moment on, in the case of times identical to a hundredth of a second, awarded the victory ex aequobut Tim McKee remained forever with his Olympic silver around his neck.

The evolution towards digital technology it has been increasingly rapid, up to the adoption of systems capable of recording times down to a millionth of a second. They have been introduced electronic starting guns to eliminate any advantage due to the speed of sound in air, false starts are detected by pressure sensors installed on the starting blocks, and the role of the judges became less and less decisive in assigning victories and decreeing defeats.

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Gunnar Larsson during training ahead of the 1972 Munich Olympics. Credit: Bertil Persson, Landskrona, via Wikimedia Commons

Artificial intelligence, RFID chips and GPS sensors: between algorithms and absolute precision

The last phase, the current one, is that of full digitalisation and artificial intelligence, still in full evolution. Modern systems no longer limit themselves to measuring time: they analyze, process and transmit a huge amount of data in real time. What were once simple stopwatches are now computers capable of managing thousands of athletes and millions of data simultaneously, using RFID chips, transponders and GPS sensors to track every movement with millimeter precision and analyzing data such as speed, acceleration, position, reaction time, heart rate. Thishuge amount of data it is processed in real time by algorithms that can predict performances, optimize race strategies and even prevent injuries.

THE’technological evolution it radically transformed the very concept of sporting competition. If a century ago it was enough to “arrive first”, today every fraction of a second is measured, analyzed and compared. Athletes no longer only compete against each other, but also against increasingly higher standards of precision. Timekeeping has become a scientific discipline in its own right, where human error has been replaced by absolute and unquestionable precision of computers.