From uniforms to equipment, the regulations around what athletes can bring to the competition must constantly adapt to address emerging technology and trends. But how do we determine what's fair?
When German swimmer Paul Biedermann set a new world record in 2009 — leaving former record holder Michael Phelps in his wake — he ignited not only a firestorm of protest but an intervention from the sport's governing body over his hightech swim gear.
But who sets the rules for Olympic events and what impact does this have on setting new world records?
In this case, FINA the governing body for swimming, was caught off guard.
In 2009 at the world championships in Rome, Paul Biedermann wore a fullbody swim suit made of smooth polyurethane. The suit was developed by engineers at a company called Arena, makers of high performance swim gear. Decked out in the XGlide, Biedermann went on to set a new world record in the 200-metre freestyle competition of 1:42.00 — beating Michael Phelps' previous record by almost a full second.
Some said the XGlide gave Biedermann an unfair advantage. Phelps' coach Brian Bowman was outraged and went on record saying, "The sport is in shambles right now, and they better do something or they're going to lose their guy who fills these seats."
What exasperated many at the time was that FINA, the international governing body of the sport, held a news conference an hour before the final to announce that the vote to ban the polyurethane suits was ratified, but would go into effect at a future date.
Why are rules key in setting sporting event records?
Steve Haake, the sports scientist and onscreen guide in The Nature of Things documentary "The Equalizer" offers a perspective from the point of view of the rulemakers.
"The job of the rules committee of any sport is to keep this balance between technology and tradition. So they like a little bit of technology, because a little bit of technology keeps the sport alive and it gives you a few world records. But traditionally, you don't want things to change too fast."
In the end, FINA decided Biedermann could keep his world record but that the Arena XGlide would be banned from competition. Today's approved suits must not cover too much skin — meaning no suit material on the arms or below the knees.
Competitors' products are submitted for approval about once a year — or more if necessary. Sports organizations like FINA make decisions about athletic gear by committee.
Uniform regulations stir beach volleyball controversy
Beach volleyball is another sport to have controversy over its uniforms — specifically for female players. The women's uniform received a noticeable makeover in 1999, when the international volleyball federation (FIVB) passed a rule requiring female players to wear bikinis — a move criticized as sexist by onlookers but not necessarily players.
"I'm kind of bummed — I like my tights," said the sport's most famous player at the time, Gabrielle Reece, who was known for wearing tights rather than a bikini suit while playing.
"You take one step, that bathing suit goes straight up," she says. "You're always yanking and fiddling."
As diagrammed in the 2015 equipment rulebook, the bikini bottom has strict size guidelines — for example the side of bikini (where it sits on the hips) can be no more than seven centimetres wide.
In early 2012, FIVB adapted the rules again to allow more uniform choices for female players. A top with sleeves and shorts for the bottom are acceptable, as well as bodysuits for inclement weather or for religious and cultural reasons.
Some players say they are used to the bikini or say it collects less sand. Unlike swimsuits for the water, the amount of material on the uniform has no clear advantage on performance.
Rules can make setting records harder
In the sport of javelin, future records are unlikely to improve upon records set in the 80s and 90s.
Why? Javelin throwers will have trouble beating the legends of the past because of how the implement itself has changed. In the mid-1980s, competitors began to throw so far that their javelins landed dangerously close to the crowd. In 1986, the rules committee responded by changing the design of the javelin for the men's competition. In 1999, the women's javelin was similarly redesigned.
That's why, in 1986, Fatima Whitbread of Great Britain set a world record that still stands today. Her distance of 77.44 metres is more than seven meters further than the contemporary athlete featured in The Equalizer, Christina Obergfoll.
With a personal best of 70.20 meters, Obergfoll has won a world championship, Olympic bronze and Olympic silver medals, and is focussed on winning Olympic gold.
Centre of gravity
The major difference between the new and old javelin is the center of gravity. In the new javelin, it's shifted forward by four centimetres, keeping the javelin's nose down and making it angle more steeply towards the ground. This seemingly small change shortens the throwing distance by 10 per cent.
To measure the effect of this change, Steve Haake watches Obergfoll, as she throws both an old and new javelin — with a caveat. "It's not really fair to ask Christina to throw an old-rules javelin and expect her to do a world record just like Fatima Whitbread.
"But what we can do is we can get her to do an experiment where she throws the old javelin and the new javelin with the same force. We'll take an average of a few throws of each, and we can work out just how much further that old-rules javelin flies," he explains.
Javelin rules are set by the IAAF, the governing body for all track and field events.
Who sets the rules at the Olympic Games?
International sports federations (like the IAAF or FINA) are responsible for governing their sports on the international level.
Federations seeking IOC recognition must align their practices and statutes to adhere to the Olympic Charter. The international federations are allowed to voice their opinions on the technical capabilities of potential Olympic host cities among other decisions made by the International Olympic Committee.
While technological advances in sport have forced governing bodies to adapt their rule books — as was the case with Biedermann's controversial swimsuit — in the javelin event, it was spectator safety that forced a change. Even so, Rio 2016 may prove to be a testing ground for new technologies and an opportunity to see if the rules are keeping up.