Dừng hoạt động. Để cơ bắp nghỉ ngơi. Kéo giãn. Thực hiện động tác tập nhẹ khi cơ lưng co thắt. Sử dụng đệm sưởi hay túi chườm lạnh. Uống đủ chất lỏng và chất điện giải.

Given the above summary, write a detailed text in English for it.
When a muscle spasm begins, stop your activity. Spasms can happen during exercise or while doing normal daily tasks. At the first sign of a spasm, stop what you are doing and try to deal with the spasm.Although they can be painful, there are generally no long-term concerns. Try massaging or rubbing the area with the spasm. This can help relax the muscle and increase blood flow to the area. Rest them for a few days after the spasm, especially if it was a back spasm. Soreness is common after spasms. Your muscles may be strained and should get some time to recover without additional stress. Make sure to gently move the muscle during this time to prevent any stiffness. You may use the affected muscle lightly, but stop using it if you feel a cramp or pain coming on. Try gentle walking or stretches, but don't twist or bend the torso. If you experience a muscle spasm or cramp, stretching can help. When you stretch, you pull the muscle in the opposite direction of the contracted muscle, elongating it. When you stretch, you want to gently lengthen and pull the affected muscle. Don't overextend the muscle. If you start to feel pain, stop. If it feels tight, hold it but don't go any further. Hold each stretch for approximately 30 seconds.  For calf cramps (Charley horse), stand a few feet from a wall. Place forearms against the wall while keeping the knees and back straight. Heels should be touching the floor. Lean forward. You should feel the calf muscles stretching. The feeling should be pleasant or neutral. If you feel any pain, stop.  For foot or calf cramps (Charley horse), sit down and flex the toes on the cramping leg upward toward the nose. You can also gently pull the foot towards your head. You should feel pulling in your calf or foot muscles. For a hamstring cramp, sit on the floor and extend your legs in front of you. Your feet should be neither pointed or flexed. Bend at the waist while keeping your back straight. Lower your chest towards your legs. Stop bending once you feel the stretch in the back of your...