You might have heard that stretching can have a negative impact on physical performance. Does this happen with all types of stretching, and how long does the effect last? A study published in The Journal of Sports Medicine and Physical Fitness offers insight into these questions.
 

Over the course of 3 days, researchers had 12 male taekwondo athletes sprint 20 meters before and after 3 types of stretching exercises: static, ballistic and proprioceptive neuromuscular facilitation (PNF). Sprint times increased after all types of stretching, and the effect lasted for 15 to 20 minutes with static and PNF techniques. Sprint times recovered after only 5 minutes with ballistic stretching.