An apparatus for treating musculoskeletal disorders comprises a plurality of light emitting diodes and a control circuit. The control circuit causes the light emitting diodes to pulse at predetermined frequencies of from 0 (continuous) to 125 Hz. The light emitting diodes themselves emit light radiation in a frequency range of 628 nanometers (+/- 5%) for the visible diodes and 850 nanometers (+/- 5%) for the infrared diodes.