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March 2004 Article Tennis Server
Top Pros (Women)
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Preventive Measures For The Tennis Player
The sun has started to shine in northern California and possibly the worst of the winter rain storms are over in our area. However, no matter where you live and play tennis -- in the tropics or a colder climate -- the sun's radiation can have negative, adverse effects to your skin. The nature of the game exposes the outdoor tennis player to prolonged periods to solar radiation. While a sunburn can be the short and uncomfortable temporary result of exposure, the long term effects include photoaging -- the wrinkling, discoloration (dark freckle-like spots) and elasticity loss of the skin -- as well as precancer lesions and a variety of skin cancers. The Society for Tennis Medicine and Science has posted a series of photos of human subjects with these conditions. Take a look at these photos. As the ozone layer around our planet has been depleting, the negative effects of solar radiation have increased. The World Health Organization has determined that in the United States from 1935 to 2001, the risk of developing the deadliest skin cancer, malignant melanoma, rose from 1 in 1500 to 1 in 71 (over a factor of 20) (Rigel, 2002) . Solar radiation is composed of both visible and invisible wavelength light, such as ultraviolet (UV) light. The UV light is the major culprit linked to the negative effects of sun exposure. Photoaging is accelerated by UVA radiation (wavelengths between 320-400 nm) and sunburn is primarily caused by exposure to UVB radiation (wavelengths between 290-320 nm). However, both forms of UV radiation have been implicated in the cause of skin neoplasms (growths/tumors). The first sunscreen was developed in 1928 and early products concentrated on blocking UVB. However, once the negative effects of UVA were determined, new agents were added to the products to provide additional protection. Compounds providing UVB protection include salicylates, cinnamates, and although not commonly used today PABA (P-Aminobenzoic Acid) and PABA derivatives. Compounds providing UVA protection include benzophenones and dibenzoylmethane. There are also "physical blocker" sunscreens like zinc oxide and titanium oxide which contain large visible particles which scatter, reflect or absorb solar radiation. Fortunately, some newer "micronized" powders are cosmetically invisible and a little more asthetically pleasing. The FDA (Federal Drug Administration) rates a sunscreen on its sun protection factor (SPF) and "substantivity" (water-resistance). SPF is an indicator of protection from UVB light, not UVA. A sunscreen rated as SPF 15, means it should take 15 times longer to sunburn with the sunscreen on than if the skin was untreated. An SPF 15 sunscreen provides 93% blockage; an SPF 30 sunscreen provides 97% blockage. While this is a small difference, Nahm, et. al. (2003) suggests tennis players use SPF 30 due to the prolonged exposure to the sun over the life of the player. They advise applying the sunscreen 15-30 before exposure to the sun and reapplication every 2-3 hours.
Use and Effectiveness Suggested SPF
(From http://www.sunscreens.net).
You also are well aware that as you sweat or you rub against your sunscreen-treated skin, the sunscreen is removed. Thus, some waterproof products have been produced. Some application methods such as roll-on sunscreens may remain on the skin longer. Don't forget to use a lip sunscreen as well. However sunscreen does not protect you from UV light 100%. It is common for individuals to expose themselves to the sun for great lengths of time because they believe they are completed protected if they wear sunscreen. In addition to sunscreen these clothing and "behavioral" practices are suggested.
Until Next Month ... Jani
This column is copyrighted by Jani Macari Pallis, Ph.D., all rights
reserved.
Dr. Jani Macari Pallis is the founder and CEO of Cislunar Aerospace,
Inc., an engineering and research firm in San Francisco. In addition
to her engineering practice, she has led two collaborations between
NASA and Cislunar, creating educational materials on the aerodynamics
of sports for pre-college students and educators. As the head of
NASA's "Aerodynamics in Sports" project, she has led a team of
researchers investigating the aerodynamics, physics and biomechanics
of tennis. The group has conducted high speed video data capture at
the US Open and research of ball/court interaction, footwork, serve
speeds, trajectories and ball aerodynamics. Pallis received a BS and
MS from the Georgia Institute of Technology, an MS in mechanical
engineering from the University of California, Berkeley and a Ph.D.
in mechanical and aeronautical engineering from the University of
California, Davis. She is a member of the Executive Committee of The
International Sports Engineering Association.
Questions and comments about these columns can be directed to Jani by
using this form.
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