Read more: 鈥�Instant Expert: Sports engineering鈥�
For millions of years, humans have used tools and technology to enhance the things we do. Throughout human evolution, our imaginative minds have invented games, which help us to learn useful physical and mental skills as well as have fun. It was inevitable, then, that technology and sport would eventually marry up, and sports engineering is the basis of that union. Any technology is considered fair game 鈥� as long as it is within the rules of sport 鈥� and sport is quicker than almost any other industry to take up new ideas. So what has shaped the engineering of sport up to now?
The birth of sports technology
Advertisement
The was one of the key moments in human civilisation. It took place in ancient Olympia in 776 BC to honour the Greek god Zeus. There was only one event, the stadion 鈥� a foot race about 200 metres down a track and back again. Soon rules were established that included simple technological advances, such as a grooved sill for the starting block and poles to mark the track. The Greeks introduced a plethora of other sports in the 300 or so Olympiads that led up to the last ancient games in the 4th century AD. Chariot racing, running in armour and the javelin all had their own technological intricacies and sets of rules.
Fast-forward 15 centuries to Victorian Britain and the industrial revolution. Societal changes had as much to do with the rise of sport as the technological advances taking place at the time. Sport profited from the introduction of regular leisure time, the rise in the middle classes, increased levels of disposable income and cheaper sports equipment produced in large quantities.
Until then, sport had mostly used readily available materials such as wood and leather. But that changed in the 1850s when , and invented ways to produce vulcanised rubber on an industrial scale. By heating a mixture of rubber and sulphur, they transformed a naturally sticky substance into a durable material with superior mechanical properties.
This transformed modern ball sports in the mid to late 1800s. Rubber bladders replaced real animal bladders, so balls could be mass-produced with almost identical properties. Rubber was also used in shoes and clothing. The introduction of the pneumatic rubber tyre by John Dunlop in the 1880s led to more comfortable bicycles and the transition from the rather cumbersome penny-farthing to the modern safety bicycle.
As professionalism increased and competitors improved, techniques to monitor and measure performance became more important. The invention of photographic film in 1885 allowed to create his classic stop-motion technique for studying galloping horses. Flash photography and cine-film followed and sports coaches began to use high-speed film with rates of hundreds of frames per second to measure athletes鈥� technique and improve their performance.
By the 1930s developments in timing allowed measurements to be made with an accuracy of 0.1 seconds. In the 1970s timing to 0.01 s became mandatory in athletics. By then it was possible to synchronise the starter鈥檚 pistol with quartz timing and light beams crossing the finish line. One consequence was that athletes appeared to get slower by around 0.2 s because the slight pause as the timekeeper reacted to the gun and activated the watch was no longer a factor (see chart).
Material World
Sports equipment designers have to work out what materials might be best for a bicycle frame or a tennis racket. With such a vast range of materials available, where do they start? One valuable tool is a materials selection chart. Routinely used by engineers, these charts show combinations of properties plotted against each other, such as density versus stiffness. The result is a 鈥渕aterial space鈥� populated with blobs, each describing a class of materials, such as wood, polymers and metals (see chart).
In 1995 Ulrike Wegst and Michael Ashby, both then at the University of Cambridge, published the first paper showing how selection charts could be used to identify which materials would work best for sports.
With rowing, for instance, an oar must be able to withstand large forces during the stroke and yet must bend just the right amount to give the athlete the correct feel. An oar should also be as light as possible to minimise energy in accelerating its mass and also to keep the boat high in the water and to minimise drag. This points towards wood, glass fibre or carbon-fibre reinforced plastics.
Or consider the pole vault. The pole must be able to store large amounts of energy without breaking, while its mass is kept to the minimum. Bamboo comes out highly in the selection process, which explains why it was still in use in the 1950s. Today glass fibre and carbon fibre are the materials of choice because they are more flexible, store more energy and can be shaped to enhance performance further.
Elite Design
New materials have changed the design of traditional sports equipment. Graphite tennis rackets, for instance, made the wooden rackets used for more than a century obsolete within a few years. The stiffer graphite frame meant that rackets could be made longer and wider, increasing the hitting area and the size of the 鈥渟weet spot鈥� where ball impact is most effective. It also shifted the frame鈥檚 centre of mass away from the long axis through the handle, so that the racket was less likely to spin in the player鈥檚 hand if the ball was off-centre. These new racket features made tennis easier for beginners to learn and, some argue, increased the speed of the elite game.
Graphite shafts are also popular in golf, and titanium has had a significant effect on the design of golf drivers. Being light, strong and corrosion-resistant, both materials are ideal for the new generation of large-headed drivers which, like tennis rackets, have a larger hitting area and peripheral weighting so that the club twists less in golfers鈥� hands when they hit a ball off-centre.
Probably at the pinnacle of sports equipment design is British bicycle designer Mike Burrows. Working with engineering firm Lotus, he applied good design principles to create a bike with a carbon-fibre frame for Chris Boardman in the 1992 Barcelona Olympics, on which he won the 4000 metres pursuit. Apart from the psychological effect of the bike鈥檚 style and beauty, Burrows鈥檚 design reduced mass and increased stiffness so that less energy was lost through bending of the frame. More importantly, it improved the aerodynamic efficiency and optimised the rider鈥檚 position.
