Running has been a competitive sport since ancient times. The original Olympic Games in 776 BC included a stadium race of 600 feet, according to the Athletic Scholarships website. Over time, running surfaces for organized track events have evolved; many competitive tracks are now made of rubber or a rubber compound. While more initially expensive than other materials, rubber and polyurethane track surfaces are durable and offer enhanced athletic performance.
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Reduced Injuries, Enhanced Speed
Stress fractures result when a bone receives significant shocks, or they can develop over time from chronic overtraining, according to Brian J. Krabak, M.D. of the University of Washington. Rubber tracks are less likely to generate stress fractures among runners than asphalt or concrete pavement, which produce much more force on leg muscles, bones and tendons.
In a 2002 report published by the "Journal of Applied Physiology," Amy Kerdok and colleagues stated that "tuned tracks" made of polyurethane produced improvement in running speeds by two to three percent and decreased the number of running-related injuries by 50 percent, compared with track surfaces made with other materials. Sprinter Usain Bolt reportedly clocked his world-record-setting times of 9.58 seconds in the 100-meter run and and 19.19 seconds in the 200-meter run on a polyurethane track in Berlin.
Cost and Maintenance
In the past, cinder, grass and clay were common materials for track surfaces. These natural materials were inexpensive in initial construction. However, maintenance for natural surfaces involves significant investment of time and money -- replacing filler material, leveling the surface of the tracks and remarking lanes. They were also adversely affected by rain, becoming soggy and sometimes unusable.
Asphalt was also commonly used for tracks. Like asphalt paving for automobile traffic, asphalt tracks become soft with summer heat and hard during the winter, according to the American Sports Builders Association. Sealing asphalt tracks with latex improves their durability.
By contrast, the initial cost of rubber and polyurethane is higher than for other surfaces.However, a well-constructed, well-maintained rubber or polyurethane track can remain in good condition for 20 years or longer. Resurfacing the track can extend its useful life for another 10 to 15 years, with a lower price tag than an entirely new track.
Increased awareness of environmental factors generated concern about the emission of volatile organic compounds, or VOCs, from rubber tracks. In a 1999 study reported in the "Journal of Hazardous Materials," F.H. Chang and colleagues took measurements from tracks constructed of synthetic rubber and polyurethane. While all the tracks produced significant levels of VOCs during construction, measurements taken two years after installation showed VOC levels at 1.5 meters above the track, the height of schoolchildren using the track comparable to those of areas away from the track.
Many rubber and polyurethane track surfaces incorporate recycled materials, such as old athletic shoes. Using recycled materials represents an environmentally friendly option for track construction.