For subjects with lumbar injuries, leg contractions could not be generated due to denervation of the quadriceps muscle. During isometric exercise, heart rate was shown to increase linearly during handgrip and leg exercises in all subjects (except for complete L2 participants), with controls exhibiting significantly higher heart rates toward the end of maximal leg extension efforts as compared to the small increases in the electrically stimulated subjects. Blood pressure also rose linearly in all groups during handgrip exercises. However, blood pressure responses differed with regards to leg exercises. Controls continued to exhibit linear increases with exercise, as did subjects with any form of T4 injury. The lumbar and T12 subjects did not show signs of any significant blood pressure changes from rest to exercise.