Stretching FAQ and Myths

adapted from: Orthopaedic Physical Therapy Secrets by Placzek, MD PT

1. What is stress relaxation?

Stress relaxation is a property of viscoelastic structures, such as a muscle tendon unit (MTU). If it is lengthened to a specific span and held in that position, the tension within the MTU decreases gradually.

This occurs during a static stretch of a muscle tendon unit (MTU).

2. What is creep in stretching?

Creep happens when an MTU is elongated to a certain length and allowed to continue to lengthen as stress relaxation occurs.

This occurs when a stretch is performed in which joint range is increased during the stretch repetition. Creep is partially responsible for the immediate increase in joint range of motion (ROM) during a stretch.

3. While stretching a muscle joint complex, what structures are involved?

• MTU (muscle tendon units)
• Ligaments
• Joint capsule
• Vessels
• Nerves
• Skin

4. What is ballistic stretching?

Ballistic (dynamic) stretching places the muscle joint complex at/or near the limits of available motion and cyclically loads it by a bouncing motion at the end range of motion.

Ballistic stretching is suitable for preconditioning a muscle joint complex for sprinting, high jump, or other activities that depend on the elastic energy in an MTU (muscle tendon units) to improve the performance of a specific movement pattern.

5. What is meant by a static stretch?

Static stretching places a muscle joint complex in a specific range of motion until a stretch is felt. The position is held for a specific period and repeated as necessary to increase body segment’s ROM.

6. What are commonly used proprioceptive neuromuscular facilitation (PNF) stretching techniques.

• Hold-relax PNF technique—the muscle to be stretched is put in a lengthened but comfortable position. The athlete is told to contract the target muscle for nearly 5 – 10 seconds. After that, the athlete is asked to relax the muscle entirely as the therapist passively increases ROM. This is repeated until no additional ROM is gained.

Intensity of the stretch is limited by the athlete.

• Hold-relax-antagonist contraction PNF technique — the targeted muscle is put in a lengthened but comfortable position. The athlete is told to contract the muscle for nearly 5 to 10 seconds. After that, the athlete is asked to relax and then contract the muscle opposing the target muscle reciprocally inhibiting the latter, actively increasing joint ROM. Intensity is limited by the athlete.
• Antagonist contraction—the target muscle is put in a lengthened but comfortable position. The athlete is told to contract the muscle opposing the target muscle reciprocally inhibiting the latter, actively increasing joint ROM. Intensity of the stretch is limited by the athlete.

7. How many repetitions of static stretch is necessary?

The optimal number of stretch repetitions is four – five. Passive stretching beyond five repetitions results in insignificant gains in muscle length and the greatest increase in range of motion is seen during the first stretch repetition.

8. How long to static stretch for flexibility is optimal?

The literature reports stretching durations from 6 seconds to 60 minutes. When looking at immediate increases in ROM, the literature recommends stretch times between 15 and 60 seconds. It’s commonly reported that prolonged stretching times impair performance.

Also, it has been reported that shorter stretch times<30 seconds result in the least performance impairments and stretch times of 6 seconds (repeated 6 times) can improve ROM while significantly lessening the negative impairment effects of static stretching.

So, stretch durations between 6 to 30 seconds seem to be optimal.

9. What is the optimal intensity of a static stretch?

Stretching to the point of discomfort (POD) is a commonly used practice and is often advocated to yield the best results. Most of the research has found that stretching to the POD cause decreased performance metrics (jump height, force production, and balance). Literature researching stretch intensities under a person’s POD reports results of improved ROM and has been found to have less negative effects on performance.

10. How often to perform a static stretching to maintain the gains of ROM?

Bohannon reported that stretch gains lasted 24 hours after a stretching session of the hamstrings. Zito reported no lasting effect of two 15-second passive stretches of the ankle plantar flexors after a 24-hour period.

This suggests that stretching should be performed at least every 24 hours.

11. If an athlete statically stretches regularly, how long will the gains be retained?

According to Zebas, after a 6-week regimen of stretching, gains realized during that period were retained for a minimum of 2 weeks and in some subjects a maximum of 4 weeks.

12. Does static muscle stretching impair performance?

According to a recent review most of the research surrounding performance metrics such as force production, vertical jump, and isokinetic power are impaired with static stretching.

Impairments may last upward of 2 hours in some cases.

In some instances, static stretching CAN IMPROVE performance of activities that require slower submaximal force production such as jogging and submaximal running or in jumping and hopping activities with longer contact times.

Also, shorter stretch durations (<30 seconds) have less negative effects on dynamic activities.

Finally, it is advocated that static stretching is better to avoid in activities that require high/rapid-speed movements or when reactive/explosive forces are required.

13. Does dynamic stretching impair performance?

Yes. However, dynamic stretching is preferred to static stretching when preparing for physical activity.

According to the research surrounding dynamic stretching, it has been reported that dynamic stretching improves athletic performance and, in some cases, improves ROM similar to static stretching. Dynamic stretching activities should be carried out at speed of 50 to 100 beats per minute.

Dynamic stretching of at least three stretch repetitions of 30 seconds’ duration per muscle group is recommended.

A 10-minute dynamic warm-up consisting of dynamic stretching, light aerobic activity, skipping, and hopping is best to prepare for physical activity.

14. Does static stretching decrease the chance of injury?

Several studies have reported that static stretching alone does not reduce injury risk. However, a dynamic warmup that consists of stretching, strengthening, balance training, and landing drills carried out for a least 3 months reduces injury.

15. Does static stretching decrease muscle soreness?

Stretching focused on the reduction of delayed-onset muscle soreness (DOMS) – muscle soreness – after exercise has not shown the effectiveness at reducing pain. Some reports say that stretching CAN reduce DOMS. But those results are statistically significant.

16. Is static stretching effective to reduce the effects of spasticity?

A systematic review by Bovend’Erdt, et al. in 2008 found the effects of stretching on spasticity to be questionable because of a lack of quality research of the subject.

17. Does static stretching reduce joint contracture?

The exact cause of joint contracture is unknown. Nevertheless, it is commonly agreed upon that neurologic and non-neurologic factors contribute to the joint contractures formation.

A 2010 Cochrane Review reported that for patients suffering with neurologic or nonneurologic joint contracture, stretching did not have clinically important immediate, short-term, or long-term effects on joint mobility.

Also, it was found that pain; spasticity, activity limitation, or quality of life did not improve when stretching was practiced for joint contracture.

18. Should I warm up before a stretch?

Should I warm up to optimize the effects of a stretch?

Not necessarily. Intuitively, it seems logical that increasing the tissue temperature before stretching results in increase viscoelastic properties of the soft tissue neighboring a muscle joint complex; but, research has reported that stretching with or w/out a warm-up gives similar results.

19. What is best stretching technique for flexibility?

A recent systematic review have shown that static stretching is superior to dynamic stretching as it relates to increasing joint ROM (however, dynamic stretching has been found to increase ROM also).

20. Does age influence the extensibility of muscle and tendon?

It does appear that with increasing age the extensibility of the muscle tendon unit (MTU) decreases (related directly to the calf muscle tendon unit). This is important regarding normal balance, ambulation, and fall prevention in the older population. Thus, a flexibility program directed toward the calf muscles appears to be a logical preventive program for the older adult.

21. Does stretching the gastrocnemius muscle in subtalar supination result in greater ankle dorsiflexion range of motion?

No.

It is often theorized that stretching the gastrocnemius muscle in a subtalar neutral position will result in increased gastrocnemius muscle length because the totality of the stretch will be directed more specifically toward the target muscle (gastrocnemius) rather than the stretch force being dissipated across the midtarsal and subtalar joints.

The literature reports that there is no big difference in the dorsiflexion ROM gains between those who stretched while maintaining the subtalar joint in supination versus pronation.

22. Does stretching alter joint position sense?

A brief stretching regimen of three stretches held for 30 seconds had no effect on knee joint position sense (proprioception).

23. Is stretching effective at reducing neck pain?

According to the neck pain clinical practice guidelines published by the Orthopedic Section of the American Physical Therapy Association in 2008, only limited literature is available about the use of stretching and neck pain. Compared with manual therapy of the cervical spine, stretching of the cervical spine has been reported to be equally effective.

Stretching of the suboccipitals, scalenes, levator scapulae, upper trapezius, and pectoralis major and minor muscle groups should be considered in patients with neck pain.

24. Is stretching effective at reducing hamstring injuries?

According to a 2012 Cochrane Review, there is contradictory evidence to show that stretching the hamstrings will reduce hamstring injury risk.

There is evidence to suggest that stretching and exercise after hamstring injury can decrease time to return to full activity.

25. Is stretching effective at reducing patellofemoral pain syndrome (anterior knee pain)?

According to a recent review, the most effective way to treat patients with patellofemoral pain syndrome is a complex physical therapy program.

It should include strength training of the hip and quadriceps abductors and stretching of the quadriceps musculature group.

26. Is stretching effective at reducing heel pain (plantar fasciitis, etc.)?

Stretching has been found to be no more effective than taping and bracing.

The main pain-relieving benefits of stretching occur in the first 2 weeks to 4 months after the onset of stretching.

Specific plantar fascia stretches may provide better short-term results versus Achilles stretching. Recommendations for frequency and number of repetitions are two to three times per day with a sustained hold of 15 to 30 seconds to as long as 3 minutes.

Bibliography

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