The Evolution and Mechanics of the 100-Metre Sprint

I love running. I was never good at it, but that has never stopped me from enjoying it. When I was an out-of-shape teenager looking for a path upward, it was the one activity that surfaced naturally. It did not cost much other than a pair of decent shoes, my time, and my effort. Neither did I have to coordinate with a bunch of teammates nor did I have to book or rent a court. Whenever I felt like it, I could just put my shoes on and go for a run. This habit has stuck with me ever since and has aged like fine wine.

A few years ago, I started doing athletic training for mid-long-distance events. After a short stint of continuous improvement, a major injury set me back and I am still recovering from it. My love for running has not waned though; I am still thankful that I can put my shoes on and go for a run whenever I feel like it. It has a meditative effect and helps me get my thoughts straight. Fun fact: I do a lot of my writing (mentally) during my runs.

Without digressing though, back when I was doing athletic training, I was very fond of 100-metre sprints. I consider this activity (the professional 100-metre sprint competitions) to be the pinnacle of sports, although both my personal experience and consensus say that the 400-metre run is much, much harder.

If you ask me, the pinnacle of sports is not all about difficulty. The 100-metre sprint is arguably one of the very first sporting events any child gets to experience, be it a neighbourhood race or an official school race. Everybody just gets it; its rules are simple; the run-of-play and outcome are easy to follow. The runners line up and sprint towards a goal in a straight line, and whoever finishes first wins — this sport is as primal as it gets!

The Olympic Games Paris 2024 are on as I write, and naturally, I have been following the progress in the running department. As I marvelled at the best human runners on the planet battling it out, it occurred to me that the sport has gotten more and more technical over the years. So, I thought I would do a technical analysis of the 100-metre sprint. While I am at it, I will also go over the significant historical changes that the sport has undergone.

The Rules of the Game

The event begins with three instructions given to the runners. The first one, “On your marks!” tells the runners to go to their starting blocks. The second instruction “Set!” tells the runners to assume pre-running posture. This is when runners go into their isometric preload — a form of static muscular loading that helps them with burst energy when they thrust forward.

This is just an extension of how we prepare for an everyday activity like getting up from a crouching position. We typically thrust the upper body upward whilst thrusting our bent legs downward to stand up. Technically, this is known as an isometric press. When runners go into a technically optimal position to thrust forward into a sprint, it is known as an isometric preload.

The final instruction is not verbal but the firing of a gun by a race official. As soon as the runners hear the gunshot, they can start running by thrusting forward.

The 100-metre sprint typically happens on the home stretch of a 400m track. Each runner gets a lane and must stay within their lane. Changing lanes would lead to a disqualification (more on disqualification later).

Post-start, the runner who crosses the finish line first wins the race. While these rules appear simple on the surface, due to fierce competition and evolution of the sport, there have been steady nuanced updates over the years.

Subtle Technicalities

Until 1977, races were hand-timed with an accuracy of one-tenth of a second (by three officials). So, runners could pre-empt starts to match the gunshot by guessing. But that changed with the introduction of automated timing.

These days, when a reaction time of less than 0.1 seconds is recorded, the start is deemed a “false start”. The officials calculate this time interval such that it considers the time it takes for the sound from the gunshot to reach the runners’ ears and the time they then have to thrust in reaction to it. Sensors are installed in the gun and the starting blocks to accomplish this.

When I watched races as a child, each runner was allowed two false starts before disqualification. I remember that the starts were long and drawn-out (and boring) back then as a different runner made a false start on each occasion.

This essay is supported by Generatebg

But in 2003, the International Association of Athletics Federations (IAAF) made a rule change which limited the entire field to one false start only. This meant that the second false starter would be disqualified even if the first false start was done by someone else.

Naturally, this gave room for tactics, as runners started deliberately false-starting on the first attempt to gain a psychological advantage over faster starters (who would be under pressure not to mess it up on the next start). In 2010, the IAAF clamped down on this tactic by modifying the rules once more — any false-starter would now be immediately disqualified.

This particular rule change was strongly contested and had its fair share of drama when world record holder Usain Bolt was disqualified in the 2011 World Championships.

In addition to this, there are weather considerations as well. Altitude plays a role in sprint times, as thinner air higher up offers lesser resistance for the runners. Any sprint time (at least) 1000 metres above sea level is marked with an “A” for this reason.

Also, headwind hinders the runners whereas tailwind assists them. However, any tailwind greater than 2.0 metres/second (m/s) makes a sprint time ineligible for official records. The tailwind conditions have to be 2.0m/s or less for the race and timings to be considered “wind-legal”.

While we are on the topic of legality for official records, why don’t we double down?

---

The Magical 10-Second Barrier

In the 2024 Olympic 100-metre final, all 8 finalists sprinted the distance in under 10 seconds. This might fool you into thinking that this is a common occurrence. But I assure you that it is not. You don’t have to take my word for it though.

At the time of writing, less than 200 human beings have ever run 100 metres in less than 10 seconds. And neither a single female nor a single human being under 18 years of age has ever done this feat.

Just to put this number into scale, astronauts are less rare than sub-10-second sprinters by a factor of more than 3! Nobel Prize winners outnumber sub-10-second sprinters by a factor of about 5!

These are extremely rare and special human beings. In 1968, during the US championships, 3 runners ran a sub-10-second 100-metre sprint. However, back then, both automated timing and manual timing were employed. While the manual times said that they ran sub-10-second 100 metres, the automated timing said that they ran just over 10 seconds.

However, later that year, the fastest of the three, Jim Hines clocked a sub-ten-second 100-metres (9.9 seconds) in the Summer Olympics officially measured by the automated timing equipment!

It took another ten years for another athlete to run a sub-ten-second 100 metres. But they still could not better Hines’ time. His record stood for a shocking 20 years! That’s how hard a sub-ten-second 100 metres timing is.

After this period though, the number of athletes running a sub-ten-second 100 metres has been steadily increasing, with the current world record being held by Usain Bolt in 2009, when he sprinted 100 metres in 9.58 seconds.

Just to reiterate how special this timing is, this record has stood for 15 years at the time of writing!

The Future of Running

It is clear from the data that runners are getting faster over time as the number of sub-ten-second 100-metre sprinters has been increasing over the past 20 years. Athlete Justin Gatlin maintained his ability to sprint sub-ten-second 100 metres for 18 years.

In 2016, athlete Kim Collins became the first human being to have run a sub-ten-second 100-metres at 40 years of age (9.93 seconds). It is worth noting here that Collins won the gold in 2003 (13 years prior to his personal best) with a timing of 10.07 seconds.

Part of why all of this is possible is the democratisation of knowledge. In the old days, knowledge of how to train for such an elite level of performance was kept secret within the top-level circles. These days, anyone with the will and discipline can read up and give it a shot.

Furthermore, there have been steady technological improvements as well when it comes to the surface of the track, the responsive material in shoes like carbon fibre, etc.

All of this makes Jim Hines’ feat even more commendable because back when he cracked the 10-second barrier, he ran on a cinder/dirt surface (non-synthetic) at/around sea level.

I humbly thank you for reading and hope that you got new insights into the world of running after reading this essay.

---

If you’d like to get notified when interesting content gets published here, consider subscribing.

Further reading that might interest you: 

• How To Tame Running Injuries
• How To Understand Computational Irreducibility?
• Polls Mislead Most Of The Time. Here Is Why?

---

References and credit: Worldathletics, alltime-athletics, and Outperform.