Stretching helps improve range of motion, and may decrease muscle soreness when done before or after exercise. Stretching cold muscles, however, can cause injuries. That’s why it is always important to warm-up your muscles before you stretch. You can warm- up with 5-10 minutes of walking, cycling, jump roping, etc. After you complete your primary workout, you can also do stretching exercises. This can help to relax and balance tension on the muscles that have just been exercised.