The NBA has a strict dress code. Sometimes it looks more like Paris Fashion Week when NBA players enter the locker room than a pre-game gathering. The NBA has a strict dress code, which applies to players before games, during post-game interviews, and all benched players. Passed in 2005 by commissioner David Stern, the code requires players to adhere to "business casual" at these times. Karl Gehring - Getty Images
Players can personalize their sneakers. It wasn't until the 2018-2019 NBA season that the regulations loosened around athlete's footwear. First, the league had a strict black and white shoe policy, then players were allowed to wear their team's colors. Now, players can wear any color or style and can even write and draw on them. Paul Bereswill - Getty Images
Twitter wars are banned. In 2017, the NBA had it with players settling things in the Twittersphere, rather than on the court. As a result, they updated their social media policy and advised all players to avoid engaging in "twitter wars." TOM MIHALEK - Getty Images
Social media is off-limits during games. Both the NBA and the NFL have strict rules in place to prevent their athletes, benched or not, from engaging in social media during the game. The NBA defines a game as 45 minutes prior to tip-off until "after the postgame locker room is open to the media and coaches and players have first fulfilled their obligation to be available to media attending the game." Michael Zagaris - Getty Images
You can't twerk after an NFL touchdown. The NFL is very specific when it comes to post-touchdown celebrationsthey even have their own set of guidelines devoted to it, which prohibits players from twerking after a big score. Michael Reaves - Getty Images
Be careful when spiking the ball. According to the aforementioned NFL celebration rules, you should spike the ball with caution. If the spiked ball appears to be directed at an opposing player, it could be grounds for a yellow card and a hefty fine, as Patriots player Rob Gronkowski found out in 2011. Mark Brown - Getty Images
Inhalers are off-limits. After concerns that inhalers would be used to boost breathing capacity and give unfair advantages, the NFL and NBA banned them, unless absolutely necessary. The World Anti-Doping Agency (WADA) also banned the medication and heavily regulates athletes using them . Tom Szczerbowski - Getty Images
Cheerleaders should be prepared for weigh-ins. The cheerleaders for the NFL are some of the most elite in their sport and, as a result, have to follow A LOT of rules. One of the strictest we've heard is they're subjected to weigh-ins before competition, according to a former cheerleader . Scott Halleran - Getty Images
Eating in uniform is a big no-no. When two former Buffalo Jills cheerleaders sued the franchise, the team's handbook became public . Among loads of rules the women had to follow, from hygiene to appearance, was that a cheerleader should never be seen eating while wearing their uniform. Tom Szczerbowski - Getty Images
Chewing gum is restricted, too. Chewing gum was also forbidden by the Buffalo Jills franchise, especially at in-person appearances . Rob Tringali/Sportschrome - Getty Images
Denim isn't allowed by the PGA Tour. Golf is one of the oldest sports, and with that comes a load of institutionalized rules. The biggest faux pas? Denim on the golf course, which explains why jeans are against the PGA's dress code policy . Andy Lyons - Getty Images
Shorts just became okay. In 2019, the PGA passed a rule allowing male players to wear shorts during practice and for pro-am rounds. However, long slacks are still required for official competitions. Kevin C. Cox - Getty Images
You must sign your score card. According to the rulebook, a golfer failing to sign their core card automatically results in disqualification. Signing a card in which the score is incorrect will also get you in trouble, adding a two stroke penalty . Streeter Lecka - Getty Images
You can't give or receive advice from another player. We're not sure why this has to be said, but the USGA says players aren't allowed to "give advice to anyone in the competition playing on the course other than his partner, or ask for advice from anyone other than his partner or either of their caddies," according to USGA rule 8-1 . Andrew Redington - Getty Images
Sometimes you have to take a mulligan. The sport of golf has so many rules that sometimes even the pros aren't aware of all of them. Certainly professional golfer Jesper Parnevik wasn't aware that failing to take a mulligan (redoing a shot) after the ball hit his foot would result in a penalty . Michael Reaves - Getty Images
Athletes aren't paid to appear in the Olympics. Although it may seem like Olympic athletes are showered with wealth after striking gold, silver, or bronze for their country, according to the International Olympic Committee (IOC), the athletes are not paid to appear at the games. DIMITAR DILKOFF/AFP via Getty Images - Getty Images
Olympic athletes don't have to be amateurs. It wasn't until 1971 that the IOC lifted regulation that Olympic athletes must be amateurs (receive no sponsorship or payment for their sport) to compete. The U.S. didn't amend this rule until 1978. Clive Rose - Getty Images
There are age regulations in the Olympics. The IOC doesn't have one set limit, because it varies from sport to sport, based on what the International Sports Federation decides . Michael Rougier - Getty Images
Hair can't touch the back of a gymnast's neck. Gymnastics is all about precision and the tiniest misstep can lead to a point deductionlike hair touching the back of the gymnast's neck . Hannah Peters - Getty Images
No clothing can show from under gymnast's leotards. Gymnasts have to perform flips and tricks in their leotards, and as such, they must be properly fitted . No stray straps or undergarments of any kind can peek out from underneath, without facing deductions. Lars Baron - Getty Images
Even the tape gymnasts wear must blend in. Bandage tape used to secure an injury must be as inconspicuous or "non-intrusive" as possible, according to the USA Gymnastics rule book , which is why competitors match it to their skin color. Andreas Rentz - Getty Images
Boxers must shake hands with their opponent. Although boxing may seem archaic in nature, sportsmanship is encouraged, as opponents are required to shake hands with one another before the match and again before the final round. Lars Baron - Getty Images
Boxers have to keep their mouth guards in. Per safety requirements, a fighter's mouthguard must be in at all times during the match. It's also against the rules for a player to attempt to obtain a break in the match by deliberately spitting their mouth guard out so don't even try. Ed Mulholland - Getty Images
Swimmers should shave their bodies before a meet. Ever wonder why? Swimmers shave their bodies before competition as a means to remove the dead cells from the top layer of skin, which makes their skin more sensitive and helps them acclimate to the water . David Ramos - Getty Images
The MLB is against catching a ball in your hat. By any means necessary doesn't really fly in Major League Baseball. In fact, if an outfielder catches a ball with his hat, the opposing team is awarded three bases . Ed Zurga - Getty Images
Ambidextrous pitchers have to pick one arm. If you're an equally talented pitcher in both arms, you have to announce which arm you're going to be pitching with before the game and you can't switch mid-game. If your chosen arm gets injured, you have to announce a switch and aren't allowed to warm up your new arm. Joe Robbins - Getty Images
Tennis players must wear all-white in certain tournaments. There's a certain formality that comes with professional tennis and no tournament celebrates tradition like Wimbledon. All players are required to wear tennis whites for their matchesnot off-white or cream. Rob Newell - CameraSport - Getty Images
Compression suits are now allowed. When Serena William donned an all-black "catsuit" at the French Open in 2018, the tournament responded by banning the ensemble. After the new mother explained that she wore it to reduce the risk of blood clots while playing postpartum, the World Tennis Association revised its rules to allow compression suits on the tour circuit. Anadolu Agency - Getty Images
Your hat can't drop. According to the International Tennis Federation's Hinderance rule , if a player's hat falls off during play, or a ball falls from their pocket, their opponent can call to replay the pointeven if they lost. Icon Sportswire - Getty Images
NHL players face penalties for fighting. Fisticuffs, as it was first called in hockey's rule book, has been a part of the sport since the early 20th century. But there are more restrictions today. The NHL's rulebook states that players can face time in the penalty box based on the referee's discretion. Lino Mirgeler/picture alliance via Getty Images - Getty Images
But fighting is still a huge part of the game. A recent interview with the NHL's commissioner, Gary Bettman, revealed that there are no plans to modify the rule book anytime soon to ban fighting altogether. Boston Globe - Getty Images
Players can't tuck in their jerseys. In 2013, the NHL adapted its equipment rules , making it a penalty offense for players to tuck the back of their jersey into their pants, as it prevents their number from being visible. B Bennett - Getty Images
Hockey has a very specific rule about blood. As an intense sport, sometimes there are injuries in hockey. But according to the NHL's rule book, in order for high-sticking to count as a double-minor penalty , the referee must evaluate, which usually comes down to whether or not blood was drawn. Icon Sportswire - Getty Images
There's no left hand usage allowed in Polo. Since the official rule change in 1974, all Polo players must play with their stick in their right hand , as the contact of a right-handed player versus a left-handed player was considered dangerous. Joel Auerbach - Getty Images
Soccer players can't remove their shirts. Since the rule change in 2004, soccer referees have been able to hand out yellow cards to any player who breaks FIFA's rule and removes their jersey in a celebratory manner. OLI SCARFF - Getty Images
Biting is strictly forbidden. Luis Surez has a no-bite clause in his contract after receiving a four-month suspension from the league for biting his opponent during a match. Alex Caparros - Getty Images
Jockeys have to meet weight requirements In order to add the least possible weight to a horse's back, jockeys are required to meet slim weight requirements. They're weighed before each race and many have spoken out about the negative ramifications it has on them . Alex Davidson - Getty Images
Jockeys must carry whips during races. If you've watched a race like the Kentucky Derby, you've seen the long whips that accompany the jockey. For safety reasons, the jockey is required to carry the whip, even if they don't choose to use it on their horse during the race . Rob Carr - Getty Images
Not just any onecan invest in a sports team. It turns out there's a lot of regulation around who partners with which franchises. When Kevin Garnett was playing for the Boston Celtics, he was blocked by the NBA from investing in the soccer club, AS Roma. You see, the Celtics' owner had a majority share in the soccer league and the NBA found it to be a conflict of interest . Boston Globe - Getty Images