The joints in the human body have different ranges of motion due to their structure. Some joints can only move in almost one direction, such as the elbow and knee joints; others have a wider range of motion, such as the shoulder, hip, wrist, and ankle joints. There is a limit to the range of motion of a joint, and once this limit is exceeded, damage will be done to the joint. There is a technique called grappling in Chinese kung fu, and one of the important aspects is anti-joint grappling. Once a joint is controlled in the opposite direction, it is easy to break when force is applied. This is the effect of external force, and self-force should not be used excessively on joints, especially in the opposite direction. Since the structure of human joints is exceptionally precise, the slightest carelessness in self-exercise can damage them. Many of the popular yoga asanas nowadays exert force on the joints in the opposite direction. Yoga claims to be a great way to move and exercise the spine, but the reality is that a large number of yoga postures and exercises can damage the spine and other joints in the body. Many yoga practitioners have suffered damage to the spine, resulting in spinal injuries and functional deterioration, and in severe cases, spinal fractures and nerve injuries, resulting in paraplegia. The human spine, because of its structure, is only suitable for bending forward, not backward or to the sides. There are a lot of yoga asanas that bend the spine backward. These asanas will cause excessive pressure on the vertebrae to the discs, which will hurt the discs and cause injuries and aging of the discs. In yoga instruction, there is a standard paraphrase that says “reach the limits of your body” and the more you stretch, twist and bend the better. Yoga asanas that bend the spine backwards are against the structure of the human body, and the forced force required to “reach the limits of the body” is bound to damage the spine. Those difficult yoga postures that bend the spine backwards will damage the spine. Some simple yoga asanas, such as the Cobra pose, can also damage the spine if the spine is pushed backwards. The spine is also not suitable for excessive bending to the sides, such as triangle pose and other similar yoga asanas, which can also damage the spine. There are acute and chronic injuries to the spine from yoga asanas. Acute ones require hospitalization immediately, but the kind of damage to the spine that accumulates slowly, from the slightest to the most obvious, is not easy to notice at first, and by the time the pain becomes obvious, the situation is already very serious. It was once reported that a yoga practitioner, who was only thirty years old, had already aged to sixty years old due to the practice of yoga. This is not an isolated case, but spinal injuries are common among yoga practitioners, although some have obvious conditions and others have mild ones. Some practitioners who are new to yoga feel comfortable after practicing asanas that bend the spine backwards. This comfort is because the damage to the spine is relatively mild when you first start practicing yoga, and these backward bending yoga postures can move the stiff back muscles that are not normally active, so the practitioner will feel comfortable at first. When the practice is longer, the damage to the spine will accumulate, and then the comfort will become pain.