You can often see old people walking like this on the street, hunched over. So we have formed a view that as soon as people get old, they will become such a hunched posture and their height will become shorter. It is true that hunchback is related to our age, but more hunchback is related to a very important muscle – the iliopsoas muscle. The iliopsoas muscle is composed of the iliopsoas muscle and the psoas major (and in some people, the psoas minor). The iliopsoas muscle is fan-shaped and originates from the iliac fossa; the psoas major is long and originates from the lateral and transverse processes of the lumbar vertebral body. Downward the two muscles meet, passing through the deep surface of the inguinal ligament and ending at the lesser trochanter of the femur. The reason why the iliopsoas muscle is very important, as the title says, is not only because the iliopsoas muscle is the main hip flexor, and many movements in daily life are inseparable from the iliopsoas muscle, but also because tension in the iliopsoas muscle can easily lead to the following problems: iliopsoas syndrome: the iliopsoas muscle and the iliopsoas tendon pass through the muscle gap and penetrate the pelvis together with the femoral nerve, and the lateral femoral cutaneous nerve also accompanies it. Whereas the iliopsoas muscle gap is relatively firm and narrow, consisting of the inguinal ligament anteriorly, the pelvis posteriorly and laterally, and the fascial band and iliopubic arch medially, an enlarged or shortened (thickened) iliopsoas muscle passing through this narrow outlet may cause nerve entrapment (similar to the pear-shaped muscle entrapment of the sciatic nerve). Thus, damage to the iliopsoas muscle causes the iliopsoas syndrome by jamming the nerve. Iliopsoas syndrome is a condition that occurs with pain in the front of the hip joint, with a clear pressure point at the root of the thigh, inability to walk with a straight back, and episodes of pain mostly induced by sudden hip flexion movements. In contrast, the posterior lateral branch of the spinal nerve can be traced from the lumbar or hip along its nerve route to numbness or soreness in the posterior lateral thigh, and sometimes it can also be reflected to pain in the groin, and there is usually no clear pressure point when palpated, and the pain is mostly induced by bending at the waist during the attack; it should not be difficult to distinguish the two. Iliopsoas muscle injury is also prone to lower cross syndrome: long-term sedentary people, due to prolonged flexion of the hip joint leads to the iliopsoas muscle in a state of tension and shortening, while the gluteus muscle is basically in a state of idle relaxation and weakness due to prolonged sitting. If the abdomen is too large due to obesity or pregnancy, or if the center of the abdomen is shifted forward due to long-term wearing of high heels, the abdominal muscles are stretched and relaxed, and the back muscles, such as the erector spinae, are pulled backward by the transverse abdominis muscle, which is bundled across the erector spinae, and the convex abdomen reacts to the erector spinae, causing excessive tension in the erector spinae. At the same time, when nerve control of a muscle is increased, it naturally inhibits the control of the antagonist muscle of that muscle. For example, if the recruitment of the iliopsoas muscle is increased and shortened in inferior cruciate syndrome, then the control of the antagonist muscle (gluteus maximus) is reduced. If the abdominal muscle is elongated and control is weakened, then nerve control of its antagonist muscle (erector spinae) is increased. The human body is tense due to the shortening of the iliopsoas and erector spinae muscles, the gluteus maximus and abdominal muscles are relaxed and weak, there is a special pathological posture, that is, the abdomen, hip flexion, hip sagging – cross body posture iliopsoas muscle is too tense can also cause dysmenorrhea we all know that the pelvis is the base of the body, it supports the abdomen, has an important function of protecting the internal organs and reproductive organs. Deformation of the pelvis can affect the pelvic organs and reproductive organs. The tilting of the pelvis distorts the original shape of the uterus, ovaries and intestines, so that the flow of body fluids is impeded or even partially lost, resulting in poor blood circulation and accumulation of symptoms such as coldness, dysmenorrhea and, in severe cases, even abdominal cramps, reduced appetite and lumbago. The best way to improve pelvic blood flow at this time is of course to return the pelvis to a neutral position, adjust the shape and volume of the pelvis by rehabilitating the sacroiliac joint, increase its joint mobility to increase the spatial compensatory capacity of the pelvis, which can directly reduce the internal pelvic pressure and thus achieve good clinical results The lumbaris major muscle is connected to the lumbar spine. The psoas major muscle is attached to the lumbar spine, descends to the groin, and fuses with the iliopsoas muscle to attach to the lesser trochanter of the femur. It can tilt the pelvis forward and cause anterior lordosis of the lumbar spine by pulling the lumbar spine forward and pressing downward and backward on the anterior inferior aspect of the ilium. The clinical importance of the psoas major is divided into direct and indirect: indirectly, it is the effect of the psoas major on posture, while directly, it causes pain in the back, abdomen and groin and thighs. And since the pain caused by the psoas major may involve internal organs, it will be very effective to deal with the psoas major in dysmenorrhea patients with reduced appetite. The above-mentioned points are the symptoms of the iliopsoas muscle after tension, and finally I would like to talk about why the tension of the iliopsoas muscle needs strengthening: some people may say that since the iliopsoas muscle is easy to tension, then why do we need to strengthen it? The more you strengthen your posture, the more incorrect it is. In fact, tension in the iliopsoas muscle shows its lack of strength. Especially for the middle-aged and elderly, the iliopsoas muscle should be strengthened because going up and down stairs and walking are things we have to do in our daily lives, and these require hip flexion, so if the iliopsoas muscle is not strengthened, it will lead to difficulties in hip flexion and affect the function of daily life. However, since the iliopsoas muscle is easily strained, strengthening is usually continued after it has been released. The main method is to fix the proximal lumbar attachment of the iliopsoas muscle and use hip flexion to exercise the iliopsoas muscle.