Do you want to enhance your workouts and activities of daily living? Then improve your flexibility through stretching! To help you understand how to stretch in a safe, effective manner, Len Kravitz, PhD, program coordinator of exercise science and a researcher at the University of New Mexico, Albuquerque, shares guidelines and strategies for stretching.

5 FAQs About Flexibility

1. How long should you hold a stretch for flexibility improvement? The American College of Sports Medicine (ACSM 2006) recommends holding a stretch from 15 to 30 seconds.

2. What is the optimal number of times to repeat a stretch? According to ACSM (2006), 2–4 repetitions is optimal, as further repetitions do not provide additional benefits.

3. How many days per week should you stretch? Each person differs, but ACSM (2006) suggests 2–3 days per week as a minimum, although 5–7 days per week of some type of stretching routine would be ideal for most persons.

4. What is the best flexibility method? In a review of 27 peer-reviewed studies on range-of-motion (ROM) techniques, Thacker et al. (2004) noted that all methods have been shown to be very effective in improving ROM, with no clear best method.

Several studies show proprioceptive neuromuscular facilitation (PNF) to be superior to static and dynamic, whereas other studies show several stretching methods to be equally effective (Haff 2006). Sharman, Cresswell and Riek (2006) contend that since PNF stretching improves passive and active ROM, it may provide additional functional benefits. (Consult with a certified personal trainer for information on different types of stretching.)

5. Will using heat packs before stretching enhance ROM? Knight and colleagues (2001) compared static stretching of the plantar-flexor muscles preceded by no warm-up, active exercise, hot packs (superficial heat before stretching) and ultrasound (deep heat before stretching) in 97 subjects (59 women, 38 men) who had limited dorsiflexion ROM. All experimental groups increased active and passive ROM, but the deep-heat intervention was the most effective. This study validates the efficacy of deep heat, which is often used by athletic trainers and physical therapists in their postrehabilitation efforts to help clients return to full activities.

Flexibility Guidelines

Here are some useful guidelines for your stretching routine.

1. Assess your flexibility to pinpoint strengths and weaknesses. For help, work with a certified personal trainer. (See to locate trainers in your area who can design a stretching program geared for you.)

2. Make sure muscles are appropriately warmed up before you stretch.

3. Perform stretching at least 2–3 times per week, and ideally 5–7 days per week.

4. Stretch all major muscle groups as well as opposing muscle groups.

5. Focus on the muscles involved in the stretch, minimizing the movement of other body parts.

6. Hold stretches for 15–30 seconds. Stretch to the limit of movement, not the point of pain. The limit of movement is referred to as the “endpoint” of the stretch.

7. Keep your breathing slow and rhythmic while holding stretches. Exhale slowly as you extend to the endpoint of the stretch. As you exhale, the diaphragm and thoracic-cavity muscles are relaxing, thus promoting a more effective relaxation of the target muscles.

8. Stretch the muscles in various positions, as this may improve the overall ROM at the joint.

9. Stretch after each vigorous workout to encourage mind and body relaxation.

10. If the stretch yields pain, back off the movement and make sure the stretching technique is correct. It may be necessary to try another position or a different stretching exercise (or method).


ACSM. 2006. ACSM’s Guidelines for Exercise Testing and Prescription (7th ed.). Philadelphia: Lippincott Williams & Wilkins.
Haff, G.G. 2006. Roundtable discussion. Flexibility training. Strength and Conditioning Journal, 28 (2), 64–85.
Knight, C.A., et al. 2001. Effect of superficial heat, deep heat, and active exercise warm-up on the extensibility of the plantar flexors. Physical Therapy, 81 (6), 1206–14.
Sharman, M.J., Cresswell, A.G., & Riek, S. 2006. Proprioceptive neuromuscular facilitation stretching: Mechanisms and clinical implications. Sports Medicine, 36 (11), 929–39.
Thacker, S.B., et al. 2004. The impact of stretching on sports injury risk: A systematic review of the literature. Medicine & Science in Sports & Exercise, 36 (3), 371–78.

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