Marathon runners are wiry, basketball players are human skyscrapers and weightlifters are short, squat, muscular beefcakes. Gymnasts are petite and as bendy as pipe-cleaners, while swimmers have hands and feet like in-built flippers. It is said that choosing your parents is the most important step towards reaching the top in sport, with genes determining physique and how your body functions.

So if you are not genetically blessed, should you kiss goodbye to hopes of being a sports champion at birth?

Experts say that body build is a crucial factor in determining aptitude for sport. Professor Andy Jones, the chair of applied physiology at the University of Exeter’s school of sport and health sciences, goes as far as to say that “success at elite level is largely down to nature” rather than nurture. “In Olympic finals, the importance of body type is quite obvious,” he says. “The build of a marathon runner, for instance, is very different from that of a hammer thrower or hockey player.”

Professor Richard Davison, the chair of the British Association of Sport and Exercise Sciences and an exercise physiologist at Napier University in Edinburgh, agrees. “If you are very short, you are never going to be a top-class basketball player. And if you are too tall, you will not make a world-class gymnast. It is not just physical leverage issues that make it difficult for people with long limbs to perform rotation movements, but tall gymnasts would be penalised by judges for not looking linear and elegant.”

Rowing speed is predicted by body size

Quite how exact the emerging science of kinanthropometry (the measurement of body shape, size and limb proportion) can be was demonstrated recently by Dr Niels Secher, an exercise scientist at the University of Copenhagen. Dr Secher attempted to predict the speed of competitive rowers based only on their body size and the weights of their boats. He was accurate to within 1 per cent. Size matters in rowing – elite male rowers are tall, muscular and weigh as much as 250lb (17st) but have low levels of body fat – and Dr Secher says that “bigger muscles allow them to use more oxygen, which means more power”.

Other studies have shown that limb length is an important factor in some sports. A study by Dr Clare Hencken, at Portsmouth University, has found that good footballers have long thigh muscles, and Kenyan athletes, who hold many middle and long-distance running world records, have high calf muscles, a genetic trait that is thought to enhance running technique. Sprinters, on the other hand, tend to be tall and muscular but with slim lower legs and fairly narrow hips, which gives them a biomechanical advantage, says Professor Jones, and they have a genetically higher proportion of fast twitch muscle fibres than, say, marathon runners.

“A higher proportion of body fat is not disadvantageous in long-distance swimming, where fat reserves serve to insulate and fuel the body,” says Steve Garland, an exercise physiologist at the English Institute of Sport (EIS). “Although sprint swimmers are getting increasingly muscular, endurance-based swimmers can be curvy and still be successful.”

Targeting future athletes

So important a factor is body type that it is being used to identify potential champions for the London 2012 Olympics and beyond. In February, UK Sport and the EIS launched a talent identification scheme, called Sporting Giants, in which they urged potential athletes to come forward, providing they fulfilled the criteria of being tall (a minimum of 6ft 3in or 190cm for men, and 6ft or 180cm for women), young (between 16 and 25) and with some sort of sporty background.

About 4,800 people responded within months. “Four thousand of the applicants have since undergone physiological tests to assess their suitability for Olympic sports requiring tall people,” says Garland. “We have whittled it down to 60 who will be directed towards rowing, and some of the others will be tested further to see if they have aptitude for volleyball or handball.”

Sporting Giants is our first big attempt to identify future Olympic champions. It is a modern and more ethical take on the searches infamously carried out in former Soviet bloc countries and China to identify genetic ability for sport at an early age. Chelsea Warr, UK Sport’s talent identification lead officer, who previously worked on the pioneering and highly successful Australian Institute of Sport’s national talent search programme set up two decades ago, says that physical characteristics are just part of the package.

Talent scouts are also looking for “games intelligence, the innate ability some people have to be in the right place at the right time”, and “coachability”, Warr says, both vital for future champions. Even then, success isn’t guaranteed.

“It takes six to eight years of hard graft for a promising athlete to get to the point where they can think about winning medals,” she says.

Still, there is already evidence that this sort of approach works. Garland says that “talent recycling”, in which promising athletes are redirected to sports more suitable to their body type, has been successful many times. He cites the example of Anna Bebington, an all-round sportswoman who began rowing at Cambridge University in 2001 when she was 18 to keep fit, but because of her physique was picked out as having potential. She started intensive training two years later and was competing for Great Britain in the world championships by 2005. Likewise, Shelley Rudman switched from the 400m hurdles to take up skeleton bob four years before winning a silver medal at the Winter Olympics. And Jason Queally made the transition from water polo player to Olympic medal-winning track cyclist.

Enjoyment is the spur to success

Of course, there are always going to be exceptions. “In some sports, skill can overcome physical limitations to a certain extent,” Professor Davison says. “With game and team sports, this is especially true. Look at the footlballers Peter Crouch and Michael Owen; both play the same position, but they are incredibly different in stature.” Likewise, he says, there is huge diversity within some sports that allows for different body types to excel. “In cycling you get the very small cyclists who are better up hills and mountains, the bigger guys who are great on the flat and in between are the compact, muscular types who are built to win the Tour de France. In rugby there are also opportunities for different body sizes to play in different positions. So your natural build is not always a limiting factor.”

In most cases, Professor Davison says, stature and build should merely be used as a guide. Well-meaning parents should certainly not push their child into a sport simply because it seems to suit their body type. “A child will not be successful at any sport if he or she doesn’t enjoy it,” says Professor Davison. “They need to try as many sports as possible and develop as many skills as they can. You may find that they become good at a sport they enjoy, despite their size, or enjoy a sport they are good at because of their size. Whichever it is, enjoyment will provide the inner motivation to succeed.”

What shape are you? There are three classic body types. Although most people are a mixture of two, you should be able to categorise yourself according to the descriptions below:

Mesomorph Large bones and well-defined muscles, with even proportions. Tend to excel at power-based sports such as sprinting, rugby and weightlifting.

Endomorph Curvier with relatively short limbs, small hands and feet and high waists. A higher percentage of body fat and less muscle. Best at endurance-based sports, such as cross-Channel swimming.

Ectomorph Small build with low body fat and narrow hips, waists, ankles and wrists. Tend to excel at distance running.

For details of Sporting Giants and other Talent ID schemes, contact www.uksport.gov.uk

THE DRIVER Lewis Hamilton

SPORT Formula One

HEIGHT 5ft 7in (1.74m)

WEIGHT 10st 5lb (68kg)

BUILD Few Formula One drivers are taller than 5ft 9in. Generally, the thinner and lighter they are, the better. Not only does it improve the fit in the tiny cockpit, but the downforce experienced as a Formula One car grips the track means that the driver can be subjected to forces of five times the pull of gravity, where his 70kg body suddenly weighs 350kg. Muscle strength, especially in the neck, is also critical, so body fat percentage is low.

THE SWIMMER Michael Phelps

SPORT Swimming

HEIGHT 6ft 4in (1.94cm)

WEIGHT 13st 7lb (88kg)

BUILD Phelps is tall and height is an advantage for a sprint swimmer. Long bodies give swimmers an automatic edge when it comes to turning and reaching for the finish. Phelps has size 14 feet, which act like paddles in the water, and an arm span of two metres, which means that his stroke rate is highly efficient.

THE ROWER James Cracknell

SPORT Rowing

HEIGHT 6ft 3in (1.93m)

WEIGHT 15st 7lb (100kg)

BUILD Rowers are classic mesomorph shapes (see box below) with broad shoulders and long, muscular limbs, with low body fat. Although rowers’ musculature can make them heavy, the water buoys their boat and it doesn’t hinder them moving through the water. Like distance runners, rowers have a high aerobic capacity and are capable of taking in up to 300 litres of air a minute.

THE RUNNER Paula Radcliffe

SPORT Distance running

HEIGHT 5ft 8in (1.73m)

WEIGHT 8st 7lb (54kg)

BUILD Although Radcliffe is taller than many world-class female marathon runners (they average 5ft in to 5ft 6in), she has the classic ectomorph physique (see box) of a distance runner, slim with a slight build, having proportionately long legs and narrow hips. Being any taller could have been a disadvantage. Distance running requires efficiency of movement in lifting the body off the ground and propelling it forward with each stride, and that becomes more difficult the taller and heavier someone is.

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