Until 2022, a 6-6 final set meant a quick tiebreak at some majors and an open-ended marathon at others. Two record-setting matches, decades apart, are why that finally changed.

Wimbledon let a 2010 final set run to 70-68 over three days before it ever considered a tiebreak. The US Open avoided that fate by adopting one back in 1970.

Three straight years of NFL rule changes have led here: teams can now declare an onside kick at any point, any score. But the same kickoff format that allowed it also killed the classic surprise onside kick for good.

The Laws of the Game don't mandate goalkeeper gloves at all -- the real rule, which every World Cup keeper follows to the letter, is about jersey color.

The Seahawks' record $9.6 billion sale to the Khosla family didn't just need a check. It needed 24 of 32 NFL owners to sign off, and rules most fans never see.

Before a big meet, swimmers strip off nearly every hair on their bodies — a ritual with real drag-reduction science behind it and a surprisingly recent history.

Twelve strikes, not ten pins, is what a perfect game actually requires. The bonus system behind the number 300, and how rare it really is to hit it.

World Athletics has two rulebooks that decide whether a fast marathon becomes history: one for pacers, one for shoes. Sabastian Sawe's 1:59:30 in London cleared both.

LA28 plans to convert SoFi Stadium's football field into the largest swimming venue in Olympic history, built to a 50-meter standard that leaves no room for error.

FIFA's push to count every dead second didn't start this summer. It traces to a 2001 study and a 2022 directive that only tightened for 2026.

Major League Baseball has no salary cap, just a $244 million threshold, escalating tax rates, and a Dodgers front office that's turned paying it into strategy.

A single tragedy in a Las Vegas ring rewrote boxing's rulebook, cutting championship fights from 15 rounds to 12. Four decades later, the WBA is quietly weighing whether to bring the old distance back.

Three days before MLB's Aug. 3 deadline, Mike Trout and Willson Contreras each shut down trade talk in the same week, one leaning on 10-and-5 rights, the other on a negotiated no-trade clause.

F1's 2026 cars carry a new 768kg weight floor, and drivers must separately meet an 82kg minimum. The post-race scale checks both — and disqualifications follow when a car misses it.

There's no official rulebook for ranking Tour de France mountains — just a race director's formula, a stopwatch's worth of judgment, and a century of arguments over which climbs deserve the honor.

A Celtics investor refused to accept a 1979 salary cap unless the team could always keep Larry Bird. The exception the league carved out still runs free agency.

Beginning this postseason, NHL playoff rosters must fit under the salary cap for the first time ever, closing a loophole that helped build three of the last five Stanley Cup champions.

Void years make a contract look cheap on paper. The cap collects the difference later — sometimes all at once, and 2026's numbers show exactly how much.

Three players per MLS roster don't count against the salary cap the normal way, and allocation money decides how much they cost on paper.

A hard salary-cap line at $221,686,000 now decides which NBA contenders can fix their roster — and which ones just have to watch it break down.