Laser treatment on ballerina's feet.

An aluminum gallium arsenide (AlGaAs) diode laser device (Twin laser, MMOptics, São Carlos, SP, Brazil) was used. The irradiation parameters were as follows: infrared laser (808 nm wavelength) with a spot area of 0.04 cm2, and an average optical power of 100 mW operated in a continuous mode during 1 minute per point, leading to an irradiance of 2,500 mW/cm2, energy of 6 J and fluence of 125 J/cm2 per point. The laser was applied on ballerina's feet twice a week during three months.

Pressure pain thresholds (PPT) were assessed with an electronic algometer. The pressure was applied and the ballerinas were instructed to ask to say "stop" when the sensation changed from pressure to pain. Three PPT measurements were performed to obtain an average.

A continuous scale comprised of a horizontal line with 10 centimeters in length was used. All ballerinas were instructed to make a mark with a pen at any point on the line between 2 verbal descriptors, one for each symptom extreme ["No pain" (score=0) and "as bad as it could be" or "worst imaginable pain" (score=10)].

Static Standing Balance Test was performed. Ballerinas were instructed to stand on one foot to a maximum of one minute. The time was measured in seconds.