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"Your ultimate guide to stretching: when, why, how"

Writer's picture: Becca CatlinBecca Catlin

Updated: Sep 15, 2024


a  female stretching outside

Awareness of current research to the effects of stretching is alarmingly low among exercise and health professionals. A survey-based study aimed to investigate the knowledge of experts and health care professionals (i.e. sport scientists, coaches and physical therapists, orthopedic physicians) regarding the evidence for or against stretching in different practice applications found that a large percentage of these professionals were not knowledgeable about research-based evidence for the effects of stretching. Warneke K, Konrad A, Wilke J. The knowledge of movement experts about stretching effects: Does the science reach practice? PLoS One. 2024 Jan 26;19(1):e0295571. doi: 10.1371/journal.pone.0295571. PMID: 38277378; PMCID: PMC10817148. If the people we look to for guidance are hazy on best practices, based on research, how can you be sure you are on the right stretching path? This does not mean the advice is bad, the advice is likely based on personal experience, anecdotal information, and traditional approaches. Many blogs and Instagram posts are short and punchy, designed more to grab your attention than to educate you. My aim is to empower YOU to determine what is the right mobility program for you.


This ultimate guide digs into the science behind stretching gathered from hundreds of research and review articles on the topic. Yes, I too provide my subjective opinions and summaries based on 20 years of physical therapy experience and my own journey as a climber.


Lets get started by identifying what outcome your are loking to achive through stretching.


 

First determine what you hope to achive through stretching to guide your approach


My strerching goal is to:


a kid stretching on the field

Streching comes in many forms. When we talk about stretching many think static stretching where we hold a long stretch like we did in 5th grade gym class. Others think of exterme flexability such as yoga, gymnastics, or dancing.


climber doing yoga

The literature discusses may different ways to strech including:

Ballistic stretching


Feeling overwhelmed already? Hang in there fo all the details or hop to the section that seems most relevant to you.


The best techniques to improve flexibility are static stretching or proprioceptive neuromuscular facilitation (PNF) training. According to a 2024 metanalysis of 77 articles, it concludes that both of these produced greater ROM than ballistic or dynamic stretching. Konrad, Andreas, et al. "Chronic effects of stretching on range of motion with consideration of potential moderating variables: a systematic review with meta-analysis." Journal of Sport and Health Science 13.2 (2024): 186-194.


 

stretching for Flexibility: How, WhEn, Why


Static Strertching


If your goal is flexibility, static stretching is likely a great choice. Choosing what muscles to stretch is linked to what activity you want to do. Climbers need lower limb and hip flexibility, including gluts, hamstrings, adductors, and calves. Gymnasts and dancers need hip mobility and substantial spinal mobility. Sprinters however, generally, do not need significant extensive flexibility and their relative stiffness benefits their speed. Being flexible for the sake of being flexible is not necessarily a hedge against injury prevention and may not be an asset in your sport. In some sports flexibility is necessary to perform well such as gymnastics, and that is a good reason to stretch. As we age, we tend to lose range of motion (ROM) and basic tasks like bending down to tie shoes or get on socks can be difficult.  That is another good reason to create a stretching practice.


If increase flexibility is your goal, here is your recipe for static stretching of the muscle tendon units:


Frequency: Stretching should be done several times a week for best outcomes. One session a week showed minimal if any gains in ROM and 5 sessions per week seemed to show greater increases then 3 sessions but the magnitude of gains begins to taper.  Total time spent stretching per week per muscle should be at least 5 min. However, time spent stretching within a single session does not seem to have significantly greater effects for ROM gains. For example, if I hit 5 minutes a week by stretching each muscle 2 minutes per day 3 times a week or do 5 minutes by stretching each muscle 1 minute 5 days a week, the difference is ROM gains are similar. If I stretch 2 minutes per muscles 6 days a week for 12 minutes of stretching per muscle per week, that may result in some added gains versus just 5 minutes a week, but again the magnitude of the gains begins to taper.  This research shows we have some “flexibility” to design a program that fits our lifestyle.

The bottom line: Five minutes per muscle accumulated across 3+ days per week is a reasonable weekly quantity to make significant gains in muscle tendon unit flexibility.


Intensity: The research supports high intensity stretching for better gains in ROM. High intensity is 80% of the full length of the tissue, or to the point just shy of maximum range. Research on stretching past the point of pain does show good improvement in ROM. However, the gains are likely not substantially more than when stretching up to, but not into the point of discomfort. Thus, I recommend stretching to the point you feel a strong stretch along the muscle belly without pain, joint pinching, compression, or discomfort. Leave some room so that you have a little bit of motion to spare by not pushing into your end range of motion. As you hold the stretch the intensity eases, gently lean into the stretch a bit more until you feel the intensity return, continue to do this throughout your 30-60 second stretch.


PNF (Proprioceptive Neuromuscular Facilitation)


PNF is also shown to improve ROM and differs from static stretching by adding muscle contraction. PNF has long been utilized by physical therapists to restore functional range of motion (ROM) and increase strength in patients who mobility limitations. The most studied methods are contract-relax method (CR) and the contract-relax-antagonist-contract method (CRAC). The CR method lengthens the target muscle then isometrically contracts the muscle followed by a relaxation of the muscle with a passive stretch. The CRAC method follows the same procedure with the addition of contracting the antagonist (opposite) muscle to the target muscle. An example for the hamstrings is to lengthen and stretch the hamstrings, contract the hamstring isometrically in the stretched position, relax, then contract the opposite muscle (quads), then relax and passively stretch the hamstrings again. This is all done in the same position with the hamstrings lengthened.  There are more techniques to PNF and entire courses exist to lean PNF. The benefit of this type of stretching is you learn to recruit and build strength specifically in lengthened ranges of the muscle where it weaker and more difficult to recruit. If you are training your muscles in these outer range as you gain ROM, you will be better able to stabilize and protect yourself from injury in these ranges. I am a fan of this technique for climbers who are often in stretched out positions where they have to stabalize the joint and exert decent force to move their bodies.


A study conducted on dance students showed that interventions based on strengthening agonist or opposing muscles are beneficial in increasing active and passive range of movement. In this study, the strength training group focused on end of range hip flexor strength with the hamstrings in a lengthen position. This group showed improved AROM to a greater degree than the group who passively stretched their hamstrings.  This exposes the functional aspect of gaining ROM. If we do not have strength to use our gained mobility, to what degree is it helpful?


When performing PNF techniques, the intensity of the contraction can be anywhere from 20% maximum isometric contraction to 100% with most studies finding moderate 40%-70% intensity the most effective without inducing pain. Typical hold times for the contraction phase are 6-10 seconds, followed by a relaxation phase with a 10-30 second. Repeating this process 3-5 times per muscle group. PNF is more effective if completed after exercise and done at least twice a week to ensure stained benefits.

Increases in flexibility and ROM from PNF were shown after one session however, this is not permanent. To maintain gains, consistent PNF stretching over a longer timeline is required.

This is similar to static stretching where gains from 5 weeks of stretching were nearly back to base line after not stretching for 5 weeks.


Both PNF stretching and static stretching decrease strength and power immediately after stretching. Thus, they are not recommended prior to high intensity and maximal effort exercises, such as jumping, plyometrics, sprinting, cutting. These effects can last from a few minutes up to ninety minutes depending on the intensity and duration fo the stretching.


 

Stretching to improve joint mobility: how is this different then flexibility?


There is a difference between lacking mobility in a joint (including joint capsules, ligaments, and boney architecture, swelling) and lacking flexibility in a muscle. It is common for joints can lose mobility associated with injury, chronic pain, post surgery. Stiffness can be a result of muscle guarding, immobility due to pain or casting, or chronic inflammation such as arthritis.


calf stretch
joint mobilization
Ankle joint mobilization
A) Joint mobilization designed to improve gliding of the right ankle. 

B) Stretching of the right calf muscle without focus on the joint.

If the mobility limitations are from the joint, you will not feel much of a strech but you may feel pain, pinching, compression in the joint when trying to stretch or joint sorness after stretching. If this is the case, you need joint mobilization more than static stretching of the muscles.


Joint mobilization is a little trickier to do to yourself. There are some options including joint distraction which will tension the joint capsule more then muscle and also has pain inhibiting effects. Another options is mobilization with movement that use belts to fix one bone of the joint as you gently move into the restricted range. Joint mobilization of the ankle is as shown, is helpful to improve joint motion after an ankle sprain.


Joint stretches can be held for at least 10 seconds and repeated 5 reps and can be done more than once a day. They can be used to reduce pain and improve motion in the joint. They should always be done pain free.


 

Stretching as a warm-up: Does it improve performance?


The American College of Sports Medicine does not recommend the use of static stretching and instead promote dynamic stretching. Despite these recommendations, static stretching is still used in warm-ups and promoted by coaches.


A consistent body of research agrees that longer periods of static stretching (>60 seconds) cause impairments in muscle performance, such as decreases in maximal force output, explosive force, power, balance, reaction and movement time in trained, untrained and recreationally active populations.


One study showed static stretching results in significant overall decrease in the force of the quadriceps for max contraction. Force remained decreased for 120 min. A study comparing ballet dancers to resistance trained women found stretching decreased hamstrings strength in both groups of women compared to controls.


The accumulation of studies like these led to a trend toward abandoning static stretching as a warm-up prior to activity. Yet, other studies have highlighted that when static stretching is limited to <60 seconds per muscle group and incorporated into a full warm-up that includes aerobic activity (jogging, jumping, sport specific tasks) and dynamic stretching (DS), the effects on performance are typically trivial.


Static stretching may still hold a place in the athletic warm-up, but it should not be incorporated just before competition or training tasks that depend on maximal force and power production.


Dynamic stretching as warm up

Many athletes and coaches have moved toward dynamic stretching as part of a warmup. Dynamic stretching involves dynamic movements of joints through full ROM under control. Common movements including Leg Swings: Front-to-back and side-to-side leg swings to loosen the hip flexors, hamstrings, and adductors. Arm Circles: Small to large circles to warm up the shoulders. Lunges: Forward, backward, and lateral lunges to engage the hip flexors, glutes, and quads. High Knees: Running in place while lifting the knees high to activate the hip flexors and calves. Butt Kicks: Running in place while kicking heels toward the glutes to warm up the quadriceps. Torso Twists: Rotating the torso side to side to engage the core and lower back.


 Dynamic stretching has been shown to improve power (Manoel et al., 2008; Yamaguchi et al., 2007), sprinting (Fletcher and Anness, 2007; Little and Williams, 2006), and jumping (Holt and Lambourne, 2008; Hough et al., 2009; Jaggers et al., 2008).  It increases body temperature (Fletcher and Jones, 2004), and muscle activation (Hough et al., 2009).


Dynamic stretching can improve flexibility, though its primary purpose is often to prepare the muscles and joints for physical activity. Improved flexabiity likely occurse through increased blood flow and muscle temperature allowing increase ROM. Dynamic stretching is not shown to provide robust gains in flexibility.


 

Stretching for Injury Prevention


The data indicate that static stretching intervention can prevent muscle injuries, but not tendon injuries, in healthy active participants. The ability for stretching to mitigate all cause injury risk is low.

 

Injury prevention programs that are effective and can reduce injuries by at least 40% in both youth and adults. These programs that include strength training, proprioception, balance, have all been shown to be beneficial, while static stretching has not. 

Examples of injury prevention results from a few studies include: A) core muscle strength programs incorporated with injury prevention programs reduced susceptibility and risk of hamstring injuries in soccer players.

B) Strengthening the muscles acting on the foot may have a significant impact on ACL and lateral ankle sprain injury risk. Van Der Merwe, Carla, et al.

C) One meta-analysis suggests that individuals with symptoms of a knee overuse injury have lower hip muscle strength. Strength training can improve mechanical faults during loading. It is often the motor coordination, recruitment, and strength that drives injury and thus strength is the key variable to train.


In Lieu of stretchig, try strengthening for injury prevention.


Resistance Stretching


In addition to the benefit of injury prevention, studies have shown resistance training alone improves flexibility. Most of this research was done with untrained subjects yet both young and old men and women have increased mobility through stregnth training. If you have enough mobility for your sport, a training program focused on stregthening will likely maintain your mobility needs allow you to focus on strength wich is shown to be a greater predicotr of injury risk.


Stretching to Manage Injury and Pain 

In the presence of pain, inflammation, and tissue injury a reflex protective response includes muscle guarding. The area may not have full ROM, and you many feel stiff and tight. However, static stretching will not be helpful in restoring mobility in this situation. This is because the tissue is not shortened or inflexible, rather than the muscle is reflexively contracted. Stretching a guarded muscle activates the reflexive feedback loop triggering the muscle to contract more. This is a built-in protective mechanism to limit your ability to create stress on the underlying injured tissue. Gentile pain free movement to reduce edema and improve circulation will provide better results.


Stretching has unfortunately, been suggested at a treatment of muscle imbalance. It is common to strengthen the presumably weakened or lengthened muscles and to stretch the tight or shortened muscles. While the combination of strengthening and stretching shows significant improvements, there is no evidence that stretching alone improves posture or muscle imbalance. In low back pain evidence does not support the use of stretching as a treatment of muscle imbalance. In contrast, people should focus on strengthening weak muscles.


Why does it feel good to stretch?

Imbedded throughout are skin, muscles, and tendons are receptors that provide feedback on pressure, length of our msucles, rate of change in position. These receptors can also inhibit pain. A short duration gentle stretch to the muscle can provide short lived moment of comfort. Consider the tight neck and tension you feel after a few hours on the computer. A common response is to stretch your neck and top of shoulder. It feels nice in the moment, but it is never lasts long, nor does it address the root issue.


However, there is a technique with better evidence for inhibition pain. Neural mobilization produces an immediate widespread hypoalgesic effect compared to placebo. 

Neural mobilization as part of multi intervention appropach is shown to have a positive effect on pain and function for patients with low back pain and neck pain. Tensioning techniques appear to be more effective in improving pain and function in people with low back pain when compared to sliding techniques. Wolny et al. reported improved nerve conduction, reduced pain, improved functional status, and reduced subjective symptoms in individuals with carpal tunnel syndrome. Neural mobilization improves nutrition to the tissue by dispersing intraneural fluid, reducing intraneural edema by pumping edema out and reducing fluid stasis.  This improved nutrition and reduction of edema improves nerve conductivity and reduces pain.


neural mobilization

That is the long and and short on stretching. Choose the method that fits your needs. Drop me a note if you have questions.

References

Warneke K, Konrad A, Wilke J. The knowledge of movement experts about stretching effects: Does the science reach practice? PLoS One. 2024 Jan 26;19(1):e0295571.


Konrad, Andreas, et al. "Chronic effects of stretching on range of motion with consideration of potential moderating variables: a systematic review with meta-analysis." Journal of Sport and Health Science 13.2 (2024): 186-194.


Wyon MA, Smith A, Koutedakis Y. A comparison of strength and stretch interventions on active and passive ranges of movement in dancers: a randomized controlled trial. J Strength Cond Res. 2013 Nov;27(11):3053-9.

Lim W. Optimal intensity of PNF stretching: maintaining the efficacy of stretching while ensuring its safety. J Phys Ther Sci. 2018 Aug;30(8):1108-1111.


Afonso J, Ramirez-Campillo R, Moscão J, Rocha T, Zacca R, Martins A, Milheiro AA, Ferreira J, Sarmento H, Clemente FM. Strength Training versus Stretching for Improving Range of Motion: A Systematic Review and Meta-Analysis. Healthcare (Basel). 2021 Apr 7;9(4):427. doi: 10.3390/healthcare9040427. PMID: 33917036; PMCID: PMC8067745.


Garber, C.E.; Blissmer, B.; Deschenes, M.R.; Franklin, B.A.; Lamonte, M.J.; Lee, I.M.; Nieman, D.C.; Swain, D.P.; American College of Sports Medicine. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: Guidance for prescribing exercise. Med. Sci. Sport. Exerc. 201143, 1334–1359. 


 K Power, D Behm, F Cahill, M Carroll, W Young An Acute Bout of Static Stretching: Effects on Force and Jumping Performance Medicine & Science in Sports & Exercise - 2004


CD Lima, LE Brown, MA Wong, WD Leyva, RS Pinto, EL Cadore, CV RuasAcute Effects of Static vs. Ballistic Stretching on Strength and Muscular Fatigue Between Ballet Dancers and Resistance-Trained Women. Journal of Strength and Conditioning Research 30(11):p 3220-3227, November 2016.


Blazevich AJ, Gill ND, Kvorning T, Kay AD, Goh AG, Hilton B, et al. No effect of muscle stretching within a full, dynamic warm-up on athletic performance. Med Sci Sports Exerc. 2018;5


Lima, Camila D., et al. "Acute effects of stretching on flexibility and performance: a narrative review." Journal of Science in Sport and Exercise 1 (2019): 29-37. Behm DG, Blazevich AJ, Kay AD, McHugh M. Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review. Appl Physiol Nutr Metab. 2016;41(1):1–11.


Wilson, Jacob M1; Flanagan, Eamonn P2. The Role of Elastic Energy in Activities with High Force and Power Requirements: A Brief Review. Journal of Strength and Conditioning Research 22(5):p 1705-1715, September 2008.


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Behm, David G., et al. "Effects of stretching on injury risk reduction and balance." Journal of Clinical Exercise Physiology 10.3 (2021): 106-116.


Takeuchi, Kosuke, et al. "A survey of static and dynamic stretching protocol." International Journal of Sport and Health Science 17 (2019): 72-79.

Takeuchi, Kosuke, et al. "Stretching intervention can prevent muscle injuries: a systematic review and meta-analysis." Sport Sciences for Health (2024): 1-11.


Stephenson, Samuel D., et al. "A comprehensive summary of systematic reviews on sports injury prevention strategies." Orthopaedic journal of sports medicine 9.10 (2021): 23259671211035776.


Warneke K, Konrad A, Wilke J. The knowledge of movement experts about stretching effects: Does the science reach practice? PLoS One. 2024 Jan 26;19(1):e0295571.


Warneke K, Lohmann LH, Wilke J. Effects of Stretching or Strengthening Exercise on Spinal and Lumbopelvic Posture: A Systematic Review with Meta-Analysis. Sports Med Open. 2024 Jun 5;10(1):65.


Beltran-Alacreu, Hector, et al. "Comparison of hypoalgesic effects of neural stretching vs neural gliding: a randomized controlled trial." Journal of manipulative and physiological therapeutics 38.9 (2015): 644-652.


Baptista, Frederico Mesquita, et al. "Effectiveness of Neural Mobilisation on Pain Intensity, Functional Status, and Physical Performance in Adults with Musculoskeletal Pain–A Systematic Review with Meta-Analysis." Clinical Rehabilitation38.2 (2024): 145-183.


Cuenca-Martínez, Ferran, et al. "Effects of neural mobilization on pain intensity, disability, and mechanosensitivity: an umbrella review with meta–meta-analysis."Physical Therapy 102.6 (2022).


Al Attar, Wesam Saleh A., and Mohamed A. Husain. "Effectiveness of injury prevention programs with core muscle strengthening exercises to reduce the incidence of hamstring injury among soccer players: A systematic review and meta-analysis." Sports health 15.6 (2023): 805-813.


Foot muscle strengthening and lower limb injury prevention." Research Quarterly for Exercise and Sport 92.3 (2021): 380-387.


Kollock, Roger O., et al. "A meta-analysis to determine if lower extremity muscle strengthening should be included in military knee overuse injury-prevention programs." Journal of athletic training 51.11 (2016): 919-926.


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