A biomechanical model was generated in order to investigate the possible mechanisms behind reductions in muscle performance due to muscle bulging. It was shown that the proportion of fiber force contributing to the total muscle force is reduced with fiber bulging and that the cause of this reduction is due to the intramuscular pressure (IMP) created by the bulging fibers. Moreover, it was established that the amount of IMP generated muscle force reduction is determined by the extent to which muscle thickening restricts muscle fibers from shortening, thereby limiting their power contribution. It was shown that bulging can set a limit to the maximal size a muscle can take without losing force and power producing capability. Possible effects, due to bulging, on maximal muscle force in relation to both muscle length and muscle shortening velocity were also demonstrated by the model.