The common causes of calf cramps caused by stretching are muscle strain, external environmental stimuli, low blood calcium and so on. 1. Muscle strain: People who often perform activities such as high jumping, fast running and leg muscle training are prone to muscle strain. Stretching the calf muscles with force may cause the legs to exceed the normal load weight, thus leading to calf cramps. 2. Low blood calcium: it is the most common possible cause of leg cramps. Calcium ions are an important factor in helping human muscles contract, and when the body’s calcium ion content is too low, the muscles will be more prone to excitement, and the leg muscles will be prone to contraction and spasms, which will lead to leg cramps. 3. External environmental stimuli: calf cold, the brain will produce signals to make skeletal muscle contraction to produce heat to maintain the normal temperature of the legs, coupled with poor blood circulation in the legs when cold, so stretching, more likely to cause calf cramps. There are many other reasons why stretching causes calf cramps, and when the situation is serious, it is recommended to go to the hospital in time to avoid adverse effects on the body.