The American College of Sports Medicine recommends stretching each of the major muscle groups at least two times a week for 15-30 seconds per exercise.
“Generally speaking, people who have full range of motion should perform stretches that hit every major joint,” Hill says. “You would never balance just one tire on your car, and likewise you don’t want to stretch just one muscle group in your body.”
Stretching after a workout can help avoid tightness, soreness and a limited range of motion that could worsen over time, Hill says. Stretching before exercise can fatigue the muscles, especially if you overstretch.