An investigation of influence of adrenal hormones on muscle performancewas made. Human adrenal glands consist of superficial cortical layerand inner medulla. Outer cortex takesup 90%of the gland weight. The main hormone of the adrenal medulla is adrenaline. It speeds up and increasesheartbeat, improves conduction of excitation in the heart, causes contraction of radial muscles of the iris, increases efficiency of skeletal muscle. It was found that the work of muscles depends on adrenal function. If the adrenal glands are weakened, the weaknessof one or more muscles will be noticed. As sartorius and gracilis muscles are attached to the pelvic bones, their weakness during the adrenal fatigue can dislocate sacroiliac joint posteriorly. It causes back pain that occurs due to lack of stability of the pelvis. Sartorius and gracilis muscles converge in the medial line of the knee, theyadduct hip and participate in the flexion of tibia.If these muscles are weakened, loss of stability in the knee is caused. These muscles act as a dynamic ligament, protecting and supporting the knee joint in various movements. The posterior tibial muscle supports an internal longitudinal arch of the foot.The arch flattens during its weakeningthat causes tension in legs and ankles. There are problems with the stability of the foot and ankle due to the weakening of those muscles. Thereforedoctors should examine the patient's adrenal dysfunction, while the muscles are weakened.