In the last decade there has been a growing interest in infrared thermography in the field of sports medicine in order to elucidate the mechanisms of thermoregulation. The aim of this study was to describe bilateral variations in skin temperature of the anterior thigh and patellar tendon in healthy athletes, to provide a model of baseline tendon and muscle thermoregulation in healthy sprinters following a unilateral isokinetic fatigue protocol. Fifteen healthy national-level sprinters underwent unilateral isokinetic force testing and electrostimulation in which body temperature was measured before, during, and after the protocol using an infrared thermographic camera. ANOVA detected a significant difference in the time x side interaction for patellar temperature changes (p≤0.001) and a significant difference in the time x side interaction for quadriceps temperature changes (p≤0.001). The thermal challenge produces homogeneous changes evident in quadriceps areas, but not homogeneous in tendon areas. these data show that metabolic and blood flow changes may depend on the physical and mechanical properties of each tissue.