When to stretch
You can stretch anytime you feel like, or you can do so in conjunction with other activities. Just remember: After any type of physical activity—cardio, strength training or sports—stretch every muscle group you used, holding each for 30 seconds. Muscles are warmer and more pliable then, making them easier to lengthen. Vigorous stretching before exercise, when muscles are cold and less pliable, will produce less benefit and may leave tendons more susceptible to injury. A good rule of thumb is to start your workout with a five-minute cardio warm-up, stretch gently, follow your usual routine, then do more serious stretching after.