Why do cyclists shave their legs?

In the 1979 comedy Breaking Away, the hero's father is horrified to discover that his son shaves his legs. Fortunately, there is an innocent, heterosexual explanation: the boy's dream is to become a professional cyclist, and he's read that shaving your legs cuts down wind resistance. In truth, depilation would aid his road speed no more than the Verdi and Puccini he listens to, or the fake Italian accent he puts on in emulation of his sporting idols. Yet it remains a common misconception that aerodynamics explains the lack of body hair in the Tour de France. According to Stanford University's swimming coach Skip Kenney, swimmers who shave their entire body gain a 2 per cent boost in speed. But water is far thicker than air and creates more drag. Any gain in speed for a hairless cyclist would be so small as to be unmeasurable.

Professional cyclists claim there are two reasons why they shave. The first is medical. They fall off their bikes more often than one might expect, and it's easier to clean out the dirt and gravel from their wounds if their legs have been shaved. Bare skin coming into contact with asphalt at 35mph is going to tear off, so it's better that it tears off cleanly, and pulling off bandages from healed cuts is less torturous if hairs are not pulled out at the same time. The second reason is more therapeutic: the massages they receive after every stage of a race are more comfortable if they are hairless. However, there is a third more compelling explanation. The cycling writer Matt Seaton put forward the following theory in 2002: "The real reason cyclists shave their legs is very simple: it is because everyone else does it. No one likes to make a direct admission but, secretly, shaving one's legs has an aesthetic dimension: it is simply how the racing cyclist should look."

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As every oiled bodybuilder knows, smooth, polished skin looks better and allows everyone a perfect view of all your hard work. The aesthetics argument was given extra credence during the 2003 Tour de France, when the Austrian cyclist Ren Haselbacher's shorts were ripped off in a fall, revealing that his shaving regimen was far more thorough than would be necessary to keep lower leg wounds clean.

Do gloves make boxing more dangerous?

Promotional posters for boxing matches in the 19th century followed a formula: the two adversaries would be depicted squaring up to each other, with heads tilted slightly backwards and their fists held low, the knuckles pointing out and upwards. The pose looks comical nowadays, as if they are actors in a silent movie rather than pugilists.

The stance and guard were low because bare-knuckle boxing consisted largely of striking the opponent's body. The skull is an extremely hard object, and a full-force punch to an opponent's head could easily result in a broken hand. This is why so many bar-room brawls end after one punch. The "boxer's fracture" a break behind the knuckle of the little finger is regularly seen in hospital casualty departments at weekends.

The Marquess of Queensberry rules took off not because society viewed the new sport as more civilised than the old, but because fights conducted under the new guidelines attracted more spectators. Audiences wanted to see repeated blows to the head and dramatic knockouts.

By contrast, the last bare-knuckle heavyweight contest in the US in 1897 dragged on into the 75th round. Since gloves spread the impact of a blow, the recipient of a punch is less likely to be blinded, have their teeth knocked out or their jaw broken. However, gloves do not lessen the force applied to the brain as it rattles inside the skull from a heavy blow. In fact, they make matters worse by adding 10oz to the weight of the fist.

A full-force punch to the head is comparable to being hit with a 12lb padded wooden mallet travelling at 20mph. Gerald McClellan took around 40 such blows over the course of his world title fight against Nigel Benn in 1995. Even the most hardened spectators were shocked by its brutality.

Neither fighter made any great attempts to defend himself. Instead, the two stood toe to toe, trading punches. As a result, McClellan suffered brain damage that left him blind, 80 per cent deaf and paralysed.

As the bare-knuckle campaigner Dr Alan J Ryan pointed out: "In 100 years of bare-knuckle fighting in the United States, which terminated around 1897 with a John L Sullivan heavyweight championship fight, there wasn't a single ring fatality." Today, there are three or four every year in the US, and around 15 per cent of professional fighters suffer some form of permanent brain damage during their career. Worldwide, there have been over 400 boxing deaths in the last 50 years alone. The total would be far higher were it not for the advances in medical care that saved the lives of fighters such as McClellan and Michael Watson. A return to bare knuckles would be bloodier and less acceptable to mass television audiences, but one has to ask whether wheelchairs and life-support machines are any easier on one's conscience.

Why do female tennis players grunt?

Maria Sharapova currently holds tennis's grunting record with a shriek measured at 101.2 decibels, which is comparable to a police car siren. Despite objections from opponents, tennis fans and officials, she has no plans to change her habit. At press conferences, Sharapova has proudly worn a T-shirt bearing the slogan "I feel pretty when I grunt". On the strength of her results she should carry on screaming: she was uncharacteristically quiet against Serena Williams in the final of the 2007 Australian Open, and went down accordingly in straight sets. She was also hushed when Justine Henin-Hardenne brought her 19-match winning run to an end in Madrid in November 2007.

A handful of male players have also grunted their way to victory, including Rafael Nadal, Jimmy Connors and Andre Agassi, although the latter once failed to defeat Ivan Lendl in the US Open despite being allowed to go on screaming the court down in the face of his opponent's protests. But it was only in 1992 that Monica Seles made the first steps towards making grunting an issue for tennis fans. Her 83 decibels modest by today's standards inspired The Sun newspaper to create the "Gruntometer". During that year's Wimbledon tournament, Jennifer Capriati is said to have shouted at Seles to "Shut the fuck up!", while an exasperated Martina Navratilova complained that her opponent sounded "like a stuck pig". Finally, an umpire asked Seles to contain herself. Suitably warned, she lost in the final to Steffi Graf.

Action from the authorities has since been less conspicuous. When Wimbledon's chief referee Alan Mills retired in 2005, he complained that officials can only act if the offender is "shown to be making the noises on purpose, which is virtually impossible to do", and called for a crackdown. But today, thanks to Seles, Sharapova and many others, grunting is so common that it rarely provokes comment, which is odd when spectators are ordered to be quiet so as not to distract the players.

This is unfortunate, since grunting is clearly a form of gamesmanship even if, for Sharapova, it is not something done deliberately. It is rumoured that coaches are teaching players to use grunting as an integral part of their game, whether because it helps to focus aggression rather like a martial artist breaking a plank or because it intimidates one's opponent. Nick Bollettieri, the sport's most celebrated trainer, disagrees with that: "Never once has that entered into my mind. But I believe releasing your energy is good because if you don't, it tightens up the body." The celebrated American varsity coach Bill Maze said that he had never taught grunting to his students, but argues, "It's certainly strategic sometimes. The grunts seem to get louder when the point is bigger. These players are probably doing whatever they can to get an edge over their opponents."

The worst offenders insist that it is not a tactic to gain an advantage, but simply an involuntary release at a moment of exertion. However, cricketers and baseball players score sixes and home runs without bellowing, and high jumpers manage to clear the bar without shouting themselves over it. Even in tennis itself, Chris Evert and Billie Jean King played in silence, while Roger Federer, arguably the best player of all time, hits his hardest shots with barely a murmur.

As Martina Navratilova explained at the beginning of the dispute in 1992, there is more to grunting than merely irritating the opposition. The sound made by the strings of a racquet striking the ball gives the skilled player an important clue about the speed and spin of the ball they are about to face. Drowning this sound out with a loud grunt is going to deny that information to your adversary. Even if grunting does help to add power to a smash, it's important to note that Sharapova shrieks even when she lobs the ball.

Do rugby players really abide by the rules more than other sportsmen?

"Rugby is a beastly game played by gentlemen" goes the old saw, whereas "soccer is a gentleman's game played by beasts". For some traditionalists, that explains the perceived difference between the conduct of professional rugby players and their counterparts with the round ball. Rugby is played and watched by the middle and upper classes men who "know how to behave". They respect the referee because, unlike soccer stars, they are not spoilt, uncouth, overpaid prima donnas (or morons) given licence by a celebrity culture to trample sportsmanship into the turf. This is of course nonsense, and not only because rugby lacks these class associations outside England. Even in the north of the country, rugby league is a working man's game. But it is also outrageous to suggest that rugby players are any kind of saints on the field in either hemisphere.

Violent conduct is widely regarded as part of the game. Reflecting on the number of times he had been punched in the face during rucks, Scotland's Scott Murray remarked: "I just like to try and play clever. If you can tug someone back and stop them making a tackle, it helps. I get it week in, week out, so there's no reason why I shouldn't cheat a little bit. Everyone cheats; it's just trying to do it without getting caught." After his nose was broken by England's Richard Hill at Murrayfield in 2000, he explained: "He stood on me a few times, and I stood on him, and he elbowed me. Nothing you wouldn't expect in an international."

Rugby players do not even require the heat of a competitive match to provoke a mêle. Leicester Tigers and England lock Ben Kay has estimated that a serious punch-up occurs on the Tigers' training ground at least once a month. By this reckoning, the reason that rugby players, unlike footballers, never fake injury is that they would not last five minutes among their own teammates if they showed such weakness. In the soccer world, training ground "incidents" usually result in one of the parties swiftly leaving the club.

Acceptable violence does have its limits, however. In March 2001, John Hopoate of Australia's Wests Tigers league side was found guilty of shoving his fingers up three North Queensland players' anuses during a game. He claimed before a judiciary panel that he had merely been administering "wedgies" to his opponents, to which one of his victims replied, "I think I know the difference between a wedgie and a finger up my arse... It's a tough game, but there's no room for that." Other forms of gamesmanship are also regarded as more or less normal.

No matter how angry players get, there is one recourse they almost never take that is sadly a common sight on soccer pitches: mobbing the referee. That kind of thing takes place in the media instead. In one instance it was alleged that Australian loose head prop Bill Young had his international career curtailed by the Springbok coach Jake White's persistent accusations of illegal plays at scrum time. Referees were incited to pay extra attention to Young such that he suffered for the slightest infringement. Whatever the merits of the individual case, Paddy O'Brien, the International Rugby Board's refereeing coordinator, has complained of the way that coaches use the press to undermine officials and insists: "I think some coaches believe they can use the media to get the upper hand. I am determined that the World Cup will be won by the best team on the paddock, not in newspaper columns and certainly not by a coach running to a newspaper, bleating." However, for the most part, during a game at least, a rugby referee's decisions are respected by both sides for a number of reasons. One is that captains are allowed to talk to the referee and ask him to explain his decisions. This helps to defuse difficult situations, especially when the match official can call on video replays in real time to inform his judgement.

There is also the extra sanction of the sin bin where players can be sent to cool off, and the option of forcing dissenters to move back 10 metres a potentially crucial distance during a match.

And there is the nature of rugby as a higher scoring game than soccer to consider. When so many soccer matches are settled by a single goal, it is bound to be tempting for players to try to goad or con the referee into awarding a penalty. With far more scoring taking place in rugby, each decision is less significant.

Which sport has the fittest participants?

The sport of triathlon began with an argument between a group of US Navy Seals in San Diego. They wondered who were the fittest swimmers, runners or cyclists and attempted to find a way to answer the question. The solution they thrashed out was to conduct races in all three disciplines and see which they found the hardest. Furthermore, they would compete in each event consecutively which, while hardly scientific, appealed to their machismo especially when their commander decided to award the title of "Ironman" to the winner. The first formally organised ironman race to invite all-comers was staged in 1978, when 15 entrants paid $3 each to attempt a 2.4-mile swim, a 112-mile bike ride and a 26.2-mile run under the Hawaiian sun. All but three entrants made it to the finish.

"Fitness" is a term that refers to five traits: cardiovascular efficiency, muscle-to-fat ratio, strength, agility and flexibility. In this sense, there are different kinds of fitness for different sports, yet researchers have tacitly agreed upon a common currency. The preferred unit of measurement when comparing different athletes' fitness is VO2 max the maximum volume of oxygen that one can consume while exercising, expressed in terms of millilitres of oxygen per kilogram of bodyweight per minute. In 1996, a team at the University of Paris compared the VO2 max of groups of national-class cyclists, runners, swimmers and kayakers. There was little to separate the runners and cyclists, but the former had the edge over the latter with an average of 74.9ml/kg compared to 72.4ml/kg. Both were well ahead of the swimmers (59.6ml/kg) and kayakers (53.8ml/kg).

However, the researchers acknowledged that the cyclists were hamstrung by their larger body masses in this particular trial and the fact that they were operating in winter, out of season. Under different circumstances, they would normally beat the runners. Another study of top German cyclists gave an average VO2 max of 78ml/kg. Lance Armstrong's VO2 max is 83.8ml/kg. He also boasts a resting heart-rate of 32 beats per minute compared with 60-70 for the average man which rises to 201 at full exertion. According to his biographer Dan Coyle, these attributes make him "the world's greatest human power plant". He needed to be to win the Tour de France a record seven consecutive times. As Coyle put it: "The Tour is the hardest event on the planet, nothing comes close. Tour riders spend more daily energy than Everest climbers. During those three weeks they expend energy at a rate that exceeds the capabilities of all but four animal species."

Yet, there is something harder, for cyclists are not quite the fittest athletes in terms of VO2 max. That honour goes to cross-country skiers. Since they must use their arms as well as their legs to propel themselves, they are sending oxygen to the entire body. A study of elite German biathletes a sport in which competitors also have to be skilled in rifle shooting and so can be expected to fall below the standards of pure skiers found an average VO2 max of 81.7ml/kg among a group of six men. The fittest of them was on a par with Lance Armstrong. Pure cross-country skiers have reported scores of over 90ml/kg.

How do the dimples on a golf ball work?

The New Zealand cartoonist Burton Silver invented a golf ball shaped like an egg that he claimed was far superior to the ordinary version. The unique shape makes it easier to control, in that it cannot be hooked or sliced because it spins on two axes. It was, however, never likely to sweep the golfing world as it made putting impossible. Silver was not going to be defeated, and he invented "golfcross", a sport that does away with greens and uses nets instead of holes. This breakaway meant that the most important innovation in golf-ball design remains the dimple.

The first golf balls were made from wood. They were superseded by "featheries", in which a core of compressed goose feathers was stuffed inside a leather shell that was shrunk to fit. The next generation of balls, the "gutties", were made from the rubbery sap of the gutta tree which resulted in a perfectly smooth ball but one that failed to fly as far as the old. Thus the properties of dimples were discovered and designers set about bettering the natural perforations and battle scars of the old leather balls. Today's professional balls consist of a plastic shell surrounding a layer of rubber threads and a gel core, though ordinary golfers tend to use a simpler, cheaper two-piece rubber and plastic ball. Most modern balls have between 330 and 500 dimples, with the top players having theirs tailor-made with the optimum number of depressions to suit their swing.

A sphere is not an ideal shape for an object in flight.

Because the rear of the ball decreases in diameter to a point over a short distance, the air the ball cuts through is forced to come back together very quickly to fill the vacuum behind it. In the process, the air in the ball's wake breaks up into swirls and eddies that exert less force on its rear than does the more smoothly moving air to the front. As a result, the ball in flight suffers the effects of drag. This is why aeroplanes (and the helmets that speed cyclists and downhill skiers wear) are designed with tapering tails to allow the air to come back together more slowly without creating swirls and eddies. Dimples intervene by creating a thin layer of turbulence close to the ball's surface that allows the smoothly flowing air to continue its progress around the ball further than it would otherwise manage. This creates a much smaller wake. The effect is so pronounced that a dimpled ball can travel twice as far as the smooth version.

Different kinds of dimples are suitable for different weather conditions. Shallow depressions generate more backspin than the deeper variety, which means more lift and a ball that stays in the air longer. Wider dimples give a higher trajectory and a longer time in the air, but allow for less control in the wind.

Do some darts players actually need to drink alcohol?

As Eric Bristow once said: "You can take darts out of the pub, but you can't take the pub out of darts." Two-time world champion Jocky Wilson seemed to drink non-stop during his matches, usually pints of lager with vodka and Coke chasers, all to "steady the nerves". He also tried to smoke his way through as many cigarettes as possible out of the 200 a day he was given by his sponsors, Embassy. Toothless from the age of 28, Wilson preferred to leave his dentures out because he said they made him belch when he drank.

When Phil "the Power" Taylor, the game's greatest ever player, lost the 2003 Professional Darts Corporation (PDC) World Final to John Part, the commentator Sid Waddell blamed it on the champion's weight-loss regime that had seen him shed three stone in four months. But Taylor himself blamed his defeat on a tough year emotionally and now swears by regular visits to the gym.

Taking good care of oneself is now reasonably normal practice among the younger players on the circuit. The authorities behind darts are so pleased with the change in the game's image that they are pressing for it to be included in the London Olympics in 2012. "I might smoke and I might drink," said Martin Adams, captain of the England darts team, "but what has that got to do with anything? Not all darts players are fat and lazy." In January 2006, even Andy Fordham told a reporter: "I am determined to keep off the weight until we make it to the Olympics. It's a new lifestyle. I can't completely cut out the booze because I get nervous before a match and need a drink to calm the nerves."

The biggest drinkers in darts have tended to be very large men who can handle the alcohol reasonably well. They can play to a high standard despite, rather than due to, the amount they take in. Cliff Lazarenko is a case in point. The commentator Sid Waddell named Lazarenko as the thirstiest man in the game; he would routinely prepare with either 20 cans of lager or six to eight pints of Strongbow, finishing off the 10th pint by the end of a match (downing the extras during the commercial breaks, after drinking on screen was banned). Yet Waddell claimed that he had never once seen Lazarenko drunk.

Oddly, competitors in most other sports that require superlative hand-eye co-ordination, such as Olympic pistol and rifle shooting, have never claimed that they need to polish off bottles of vodka to "steady their hands". Andy Fordham's successor in the 2006 BDO World Championships was Jelle Klaasen a teetotal, non-smoking, 10-stone Dutchman. Clearly, drinking heavily is not essential for success at the high-est level.

Do teams wearing red really do better?

In 1964, Liverpool were due to face Anderlecht in the second-round tie of their first-ever season in Europe. Eager to win the psychological battle, manager Bill Shankly hit on the idea of an all-red strip that would make his giant Scots defender Ron "the Colossus" Yeats even more intimidating on the pitch.

Shankly produced a pair of red shorts to match the team jersey and the centre forward Ian St John suggested red socks to complete the new outfit. Shankly was pleased with his handiwork. "Christ, Ronnie," he said, "you look awesome, terrifying. You look 7ft tall." Anderlecht duly wilted and the Reds won 4-0 on aggregate.

Is it just a coincidence that English football's three most successful teams Liverpool, Manchester United and Arsenal all play in red, or does the colour really boost performance and rattle the opposition? After all, the similarly attired Belgium and Poland have hardly fared well in the World Cup over the years even if England's crowning moment on that stage came when wearing blood red rather than white. Statistics show that in Euro 2004, wearing predominantly red was worth an extra goal a game on average. At the very least, players find scarlet-clad colleagues easier to pick out against the green of a pitch unlike Manchester United's infamous grey strip that was blamed for a poor run of form.

Robert Barton and Robert Hill at Durham University also investigated contests in tae kwon do, boxing and Graeco-Roman and freestyle wrestling from the 2004 Olympics. These were sports in which the colours red and blue were randomly assigned to competitors. In all four sports, red won the most bouts 55 per cent overall. This advantage rose to 62 per cent in contests between competitors that experts judged to be evenly matched.

However, simply wearing red cannot turn anyone into a good competitor. The researchers speculate that red is the colour that signifies male dominance and high testosterone in primates and other animals. With red being the colour of anger, it is not absurd to expect it to be the colour of intimidation. Barton suggested accordingly that wearing red might give a sportsman a testosterone surge, while having the opposite effect on his opponents.

Red is not the only colour to make a difference to performance on the field. Between 1970 and 1986, the black-clad Los Angeles Raiders led the NFL in number of yards penalised, while the similarly attired Philadelphia Flyers were penalised for more minutes than any other team in the National Hockey League. Two hockey teams, the Pittsburgh Penguins and the Vancouver Canucks, found their disciplinary records deteriorating when they swapped from white to black uniforms. Research suggests both that black clothing incites players to worse behaviour and that the same infraction is viewed as slightly more grievous in the eyes of witnesses when the perpetrator is wearing dark clothing.

Football referees might suffer less abuse if they abolished black uniforms, but it is unlikely to happen. Neither will more teams switch their home colours to red. Former Leicester City captain Matt Elliott has commented, without irony, "I think this is a load of old rubbish. We never felt we were disadvantaged by wearing blue." Clearly the explanation lies elsewhere.

Who would win in a fight between Muhammad Ali and Bruce Lee?

While preparing for his title defence against Joe Bugner in Malaysia in 1975, Muhammad Ali announced, "I will prove to the world that I am not only the greatest boxer of all time, I am the greatest martial artist." Then, before treating the kickboxer Davis Miller to a round of sparring, he declared, "You must be a fool to get in the ring with me. When I'm through, you gowna think you been whupped by Bruce Lee." Miller reported how "I bent to the right, tossed a jab toward his belt line, straightened, snapped a long, tentative front-kick to his head. I figured it was the first kick he'd ever had thrown at him, but he pulled away as easily as if he'd been dodging feet his entire life." In that brief encounter, Ali allowed Miller to get a few hits in before knocking him senseless with two punches.

Bruce Lee would no doubt fare better than the young Miller did against the Greatest, but the end result would probably be no different. Ali was 6ft 3in tall and weighed 236lb in his prime. Lee was 5ft 7in and just 135lb when he died. If Lee were a boxer he would be a lightweight nine divisions below Ali's heavyweight class. In regular boxing there is a limited degree of movement between the weight divisions.

The first advantage people think of is the martial artist's ability to use kicks as well as punches. In any contest of champions, Muhammad Ali would be allowed to kick too just as Bruce Lee would be allowed to punch but one presumes he would rely on his fists. The second advantage is Lee's dazzling speed though frames were cut from his fight scenes to make him appear even faster. Even so, his kicks could never be as fast as Ali's punches. This is no slight against the martial artist, but simply a reflection of human physiology and the laws of physics.

Even the fastest kicks are slow compared to punches, because they require more build-up and begin from a greater distance from their target. Punches can also be followed up with more of the same, whereas combination kicks are slower, more difficult to execute and usually lose power.

Furthermore, Ali would be used to dodging punches that were much faster than Lee's kicks. So to bring his kicks to bear, Lee would need to keep Ali at a distance. Assuming that the two are fighting in a ring of limited size, Lee would probably not be able to keep out of the boxer's way for long enough. Ali himself was extremely fast for a heavyweight, but even he couldn't avoid dozens of punches from the lumbering George Foreman (realising this, he even made it part of his game plan not to try to during their "Rumble in the Jungle"). Similarly, no matter how fast Lee might be, he could not realistically be expected to dodge every blow from Ali.

Now there's an arena in which the different fighting styles can be directly compared: the Ultimate Fighting Championship. Almost anything goes in mixed martial arts, or "cage fighting", except for eye-gouging and blows to the groin. Yet, contrary to the public's expectation when the sport began, kung fu masters have fared notably badly: even worse than pure boxers. The early years were dominated by grapplers, and even today fighters stand little chance unless they have excellent wrestling skills, as so many matches are settled on the ground, either with a submission hold or with one protagonist pinned down and pummelled unconscious.

The most successful mixed martial artist of recent times is Japan's Kazushi Sakuraba. Sakuraba came from professional (that is to say, staged) wrestling, but after his promoters went bust he talked his way into the Ultimate Fighting Championship's heavyweights-only Ultimate Japan tournament in 1997. He pretended that he weighed 203lb in order to qualify and, although he was really only 183lb, he defeated a 243lb ju-jitsu champion to score the first of several victories against bigger, stronger men. One of his smaller victims was the renowned Royce Gracie, who at 180lb himself once beat a 275lb heavyweight wrestler. Sakuraba's career and those of other champions in Ultimate Fighting appear to demonstrate that grappling skills are far more effective than other martial arts or boxing disciplines in overcoming a size disadvantage. The UFC has destroyed the mystique of martial arts by showing which techniques actually work. Kung fu is not one of them.

Bruce Lee had great respect for the skills of wrestlers, but he had different priorities and recognised that their techniques were not as photogenic as the looping kicks and acrobatics that movie-goers wanted to see. He realised that his moves were only for the camera, and that the flurries of hand trapping that he learned from wing chun kung fu would be of little use in a real fight. Unlike Ali, Lee never boasted that he could take on the world. He never fought in competitive tournaments either. To then say that Lee was the best martial arts fighter in the world let alone the best fighter per se would be like saying that the Harlem Globetrotters, basketball's answer to the WWE (World Wrestling Entertainment), are the world's best basketball team.

The more valid question is not whether Bruce Lee could beat Muhammad Ali, but how he would fare against Rocky Balboa...

This is an edited extract from 'Stumped! The Sports Fan's Book of Answers', by Nicholas Hobbes (9.99), which is published by Atlantic Books. To order a copy (free P&P) call Independent Books Direct on 0870 079 8897, or visit www.independentbooksdirect.co.uk