A system and method for noninvasively determining the oxygenation of a tissue, for example, a muscle, in vivo uses optical methods to optically interrogate the tissue in both a visible wavelength range and a near infrared (NIR) wavelength range. The illuminating light is sculpted in intensity to approximately match the absorbance spectrum, for example, with the visible light having an intensity an order of magnitude greater than the NIR light. Training data is obtained from healthy patients in both the visible and NIR ranges simultaneously and used to calculate muscle oxygenation.
