Pushing The Limits
Pushing The Limits
by Rebecca Lee 27.08.08
Over the Olympic Games in Beijing, an unprecedented number of World and Olympic records were broken across numerous sports, again raising questions about the limits of human performance.
EIS Physiologist Dr. Jamie Pringle, talked to eis2win.co.uk, about how unbeatable current records are what factors influence the potential for records being broken across different sports.
World record breaking margins are now coming down to hundredths of a second and as Dr. Pringle says, the power to speed relationship in sport is the key to understanding the potential for further record breaking.
“Records come down to the physics of the sport” said Pringle. “In power oriented sports like track cycling, rowing and flat-water kayaking, where there is an aerodynamic or hydrodynamic drag, the influence of drag means that the ability to increase speed becomes progressively harder as the actual speed increases” he added.
“For example, with cycling, rowing and flat-water kayaking the relationship between speed and power is a cubic one, rather than linear. There is a more complex relationship with aerodynamics so, to put simply, to pull out a gap on your opponent becomes harder the faster you are going. In effect, the nearer you approach the very limits of human performance in these sports, the harder it becomes to find performance gains.”
“You can quantify athlete’s ability by the physical power they can produce, whether that’s at the pedals, through the paddle or through the handle of the oar. In cycling, kayaking and rowing, you’re sitting down so not carrying your body weight and therefore raw power wins out - at least once you’re up to speed. In cycling, it is proportionately even more difficult to break records. With speeds of around 50-70km/h on the track, the aerodynamic forces are large and as a result 95% of the raw power produced is used to overcome the aerodynamic resistance of cutting through the air (the rest being the rolling resistance of the tyres on the track and tiny losses from the chain and gears).”
“The power to speed relationship doesn’t apply quite so much in running, at least not in distance running because the speeds are much lower and therefore the aerodynamic resistance much less. Here, the relationship between physical ability and speed is more linear. In fact, it’s much better explained by aerobic capacity-to-weight ratios rather than raw power itself, because you are supporting your body weight as well as generating the force to propel it” said Pringle.
Perhaps the most famous of recent world records was achieved on the track in Beijing by Jamaican sprinter Usain Bolt. His achievements even more significant when you consider that whilst endurance runners suffer the impact of aerodynamics, sprinters face more of a challenge as their pace is much faster and therefore the aerodynamic resistance to overcome greater.
So in summary, many sports which demonstrate a cubic relationship between speed and power, such as cycling, sailing and rowing have recognised the impact on performance that small changes in aero and hydrodynamics can make. The effects of aerodynamic and hydrodynamic forces and demonstrated through applied research is reflected in the changing aspects of equipment, clothing design and training techniques.
In contrast, those sports which demonstrate a linear relationship between speed and power, the pure ‘fitness’ of the athlete and their aerobic capacity-to-weight ratio is one of the main limiting factors in terms of their potential maximal speeds achievable.
Photography © Getty Images