PNF stretching

What it is

A contraction between stretches

A review of stretching in healthy athletes lists PNF among the most used methods of stretching¹. A 2025 review describes it as a contraction of the target muscle, then a passive movement of the joint the other way⁷. It names three best-known forms⁷:

• Contract-relax (CR): the joint is moved to the end of its range, and the stretched muscle contracts isometrically and relaxes⁷. Then the joint is moved to a new end of range⁷.
• Antagonist contraction (AC): the contraction comes from the opposing muscle⁷.
• Contract-relax-antagonist-contract (CRAC): combines the two⁷.

A meta-analysis of 77 stretch-training studies sorts the forms another way⁴. In its passive techniques, contract-relax and hold-relax, the stretched muscle contracts and is then moved further into stretch⁴. In the active technique, CRAC, a contraction of the opposing muscle replaces that final passive stretch⁴. One variant of contract-relax, the 2025 review notes, has the contraction done with the joint in its anatomical position, the standard reference posture⁷.

How often studies use it

A scoping review (a review that maps what research exists on a topic) found PNF in 36 of 300 trials in healthy athletes¹. A 2006 review stated that the literature positions PNF as the most effective technique for gaining range, especially short-term range².

What it loads

The contraction sets the dose

A 2025 review proposes measuring PNF intensity as the force of the isometric contraction⁷. In contract-relax that is the stretched muscle’s force; in antagonist contraction, the opposing muscle’s; in CRAC, both⁷. It would measure volume by how long each phase lasts and how many cycles are done⁷.

In studies one team informally reviewed, requested PNF forces ran from 10% to 100% of maximal voluntary isometric contraction (MVIC, hardest effort, joint still)⁹. When 36 university athletes were asked for 20%, 50% and 100%, they could not match the 20% and 100% targets¹⁰. Three studies set up a PNF cycle in these ways^11,12,13:

Study	One cycle	Repeats
One session, lower leg, CRAC	15-second stretch, 6-second calf contraction at about 80%, 15-second opposing-muscle contraction	Four, with 20 seconds’ rest11
Hip adductors and abductors, CR	Stretch to discomfort, 10-second contraction at 50%, 5 seconds’ relaxation, 5 seconds’ more stretch	Three per muscle group12
72 young men with tight hamstrings, CR	6-second stretch with a contraction at 20%, 60% or 100% of MVIC	Three a day for five days13

Muscle and tendon in one session

In 17 healthy volunteers, contract-relax, static stretching and maximal isometric contractions all raised dorsiflexion (foot pulled up toward the shin) range¹⁴. Stiffness is how much force it takes to stretch something by a given amount. Contract-relax lowered muscle and tendon stiffness; static stretching lowered only muscle stiffness, and the contractions only tendon stiffness¹⁴.

What the method asks of the person

A 2025 review lists these drawbacks⁷:

• a limited warm-up effect on dynamic skills⁷;
• the need for a partner or support⁷;
• possible discomfort from contracting at a long muscle length⁷;
• possible cramp from the opposing-muscle contraction in CRAC⁷.

A systematic review (a set, checkable search of the research) of 46 trials in young healthy adults reported that no adverse effects were mentioned¹⁵.

How the body adapts

The reflex ideas, and what tested them

A 2006 review states that PNF’s range gains were traditionally put down to autogenic or reciprocal inhibition². It adds that the literature does not support this². In autogenic inhibition, as a 2025 review describes it, Golgi tendon organs make the muscle’s own motor neurons less excitable under high tendon tension⁷. These are sensors where muscle meets tendon, and motor neurons are nerve cells that drive muscle fibres. The review calls the theory uncertain, since it is unclear whether this inhibition switches on during PNF, or for how long⁷.

Reciprocal inhibition was the other proposed explanation: contracting the opposing muscle would let the stretched muscle relax^3,16. A 2004 review found the data support neither this nor the idea that contracting the stretched muscle first makes it relax³. After a contraction, it found, the stretch reflex (a fast, automatic tightening when stretched) is damped for only about 1 second³. It suggested this may come from inhibition of the muscle spindle (stretch sensor) signal, not from Golgi tendon organs³.

In 18 people aged 17 to 44, hamstring electromyography (EMG, a measure of muscle activity from its electrical signals) showed neither kind of inhibition¹⁶. Activity rose during the opposing muscle’s contraction and stayed above baseline after the muscle’s own¹⁶. The authors concluded that earlier nerve-based explanations seem inadequate¹⁶.

In 30 people, a technique the authors call agonist contract-relax gave more hamstring EMG and knee range than contract-relax or a sustained stretch¹⁷. The authors suggested range gains may not depend strongly on the muscle relaxing¹⁷.

Stretch tolerance instead

The view in 2006, that review says, proposed that PNF changes the point at which stretch is felt or tolerated². It added that the mechanism was not then known². The 2004 review named changes in stretch tolerance, or in the muscle’s viscoelastic (part springy, part fluid-like) behaviour, as possible mechanisms³. A 2025 review also names greater stretch tolerance as a possible cause of gains over weeks⁷.

The view in 2006, that review says, proposed that PNF changes the point at which stretch is felt or tolerated.

Ten men did contract-relax and static hamstring stretches in a crossover design, where each person tries every option in turn¹⁸. At a fixed angle, the two showed no difference in passive torque (turning force) or EMG¹⁸. Contract-relax allowed a larger maximal angle, which the authors read as altered stretch perception¹⁸. In the 17-volunteer study, changes in stretch tolerance were correlated with range changes after all three methods¹⁴.

Range in one session, and contraction effort

A 2025 review reports that contractions from 20% to 100% of maximum, lasting 3 to 15 seconds, were similarly effective for range in one session⁷. For range in one session, one contract-relax cycle worked as well as up to four⁷. Two trials of contraction effort disagree^9,13:

For range in one session, one contract-relax cycle worked as well as up to four.

• A randomised controlled trial assigned 72 young men with tight hamstrings to groups by chance, including a group that did not stretch¹³. With three 6-second stretches once a day for five days, efforts of 20%, 60% and 100% gave similar flexibility gains, all above no stretching¹³.
• In 56 university athletes, efforts of 20%, 50% and 100% all raised straight-leg-raise range, by significantly different amounts⁹. The gain peaked near 64%⁹.

A 2006 review’s summary held that a target-muscle contraction needs about 3 seconds, at an effort of 20% of maximum or less². It found the largest range change usually follows the first repetition².

Though the studies varied widely, its summary suggested that “active” PNF, which adds a shortening contraction of the opposing muscle, gives the greatest gains². The opposing-muscle contraction appeared to have the largest impact². A meta-analysis of 47 studies found no significant difference in one-bout range gain between stretching techniques¹⁹.

A review found range gained in one session of static, dynamic or PNF stretching usually lasted under 30 minutes⁶.

Range over weeks

Reviews disagree on how PNF programmes compare with static stretching^4,5,20:

• A meta-analysis of 77 studies found no significant difference, though PNF’s effect size (a standard measure of how large a difference is) was slightly higher⁴.
• A review of 23 long-term studies found static programmes gained more than PNF programmes⁵.
• A meta-analysis of 39 randomised trials in 1,770 healthy adults found conflicting hamstring results for hold-relax and contract-relax against static stretching²⁰.
• A systematic review of 46 trials in 1,864 young healthy adults found the evidence too weak to rank PNF against other stretches¹⁵.

A 2025 review reports a meta-analysis in which long-term range gains appeared not to depend on contraction effort, from 25% to 100% of maximum⁷. The 2006 review’s summary held that lasting change needs PNF once or twice a week². Training studies found these changes^{21,22,23,24,25,26}:

People	Programme	Range	Other findings
62 healthy people	6 weeks, calf	Up about 6 degrees	Achilles tendon stiffness unchanged21
49 volunteers	6 weeks	31.1 to 33.1 degrees	Achilles tendon stiffness fell; strength unchanged22
One study	4 weeks, quadriceps (front thigh)	Up 9.2 degrees on average	Peak torque unchanged23
18 men	8 weeks, PNF or passive stretch	Up about 19% in both	Knee flexor strength unchanged24
20 active women	4 weeks, ankle	Up 7.8%	Isometric strength up 26%25
16 athletes	8 weeks, contract-relax, one leg	Up to 6.3 degrees	Knee torque up to 21.6% against the untrained leg26

A 2025 review states that the mechanisms behind long-term gains have not been studied systematically⁷. Studies disagree on whether muscle and tendon stiffness fall⁷. The two 6-week studies of the Achilles tendon show that split^21,22.

Strength and performance

Tested straight after stretching, one review found performance changed by about −4.4% after PNF, −3.7% after static and +1.3% after dynamic stretching⁶. A 2025 review reports that PNF generally appears to lower maximal effort in sprints, jumps and lifts⁷. It also reports better stride rate and length in easy jogging⁷. Single studies found:

• In 122 volunteers, maximal plantar flexor (calf) contraction fell by 4.6% only after PNF, not after static or ballistic (bouncing) stretching¹¹. Overall, the methods did not differ in a clinically relevant way¹¹.
• In 15 men with resistance-training experience, bench press repetitions fell after PNF; static stretching had no significant effect²⁷.

In 627 athletes from flexibility-dependent sports, a review of 23 studies found a small positive effect of single PNF sessions: 1.04% against control²⁸. The authors noted that this rested on few studies with mixed results, mostly of low quality²⁸. They wrote that no firm conclusions could be drawn²⁸.

Over weeks, strength rose in two trials and did not change in three others (see the table above)^{22,23,24,25,26}.

Injury

A review found no clear effect of static or PNF stretching on all-cause or overuse injuries⁶. In the scoping review, only five assessed injury data¹. Their results did not support a role for stretching in reducing injuries¹. Authors of the 72-man trial suggested that submaximal contractions may lower the injury risk linked with PNF¹³.

Connections

PNF’s contractions are isometric, the kind of muscle work behind isometric training¹. The studies above measured muscle and tendon stiffness after PNF^14,22. They stretched the hamstrings, quadriceps and hip adductors^12,13,23.

Studies of single stretches also used PNF^{20,27,29,30,31,32}. Related stretch pages: hamstring stretch, calf stretch, adductor stretch, standing shin stretch, doorway pec stretch and wrist extensor stretch.

Sources

1. Afonso J, Andrade R, Rocha-Rodrigues S, Nakamura FY, Sarmento H, Freitas SR, et al. (2024). What We Do Not Know About Stretching in Healthy Athletes: A Scoping Review with Evidence Gap Map from 300 Trials.. Sports medicine (Auckland, N.Z.). doi:10.1007/s40279-024-02002-7 PMID 38457105
2. Sharman MJ, Cresswell AG, Riek S (2006). Proprioceptive neuromuscular facilitation stretching : mechanisms and clinical implications.. Sports medicine (Auckland, N.Z.). doi:10.2165/00007256-200636110-00002 PMID 17052131
3. Chalmers G (2004). Re-examination of the possible role of Golgi tendon organ and muscle spindle reflexes in proprioceptive neuromuscular facilitation muscle stretching.. Sports biomechanics. doi:10.1080/14763140408522836 PMID 15079994
4. Konrad A, Alizadeh S, Daneshjoo A, Anvar SH, Graham A, Zahiri A, et al. (2024). 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. doi:10.1016/j.jshs.2023.06.002 PMID 37301370
5. Thomas E, Bianco A, Paoli A, Palma A (2018). The Relation Between Stretching Typology and Stretching Duration: The Effects on Range of Motion.. International journal of sports medicine. doi:10.1055/s-0044-101146 PMID 29506306
6. Behm DG, Blazevich AJ, Kay AD, McHugh M (2016). Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review.. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. doi:10.1139/apnm-2015-0235 PMID 26642915
7. Longo S, Cè E, Toninelli N, Esposito F, Coratella G (2025). Muscle Stretching: Exploring the Impact of Different Modalities on Maximal Range of Motion and Strength with Practical Recommendations.. Sports medicine - open. doi:10.1186/s40798-025-00925-7 PMID 41201748
8. Guiu-Tula FX, Cabanas-Valdés R, Sitjà-Rabert M, Urrútia G, Gómara-Toldrà N (2017). The Efficacy of the proprioceptive neuromuscular facilitation (PNF) approach in stroke rehabilitation to improve basic activities of daily living and quality of life: a systematic review and meta-analysis protocol.. BMJ open. doi:10.1136/bmjopen-2017-016739 PMID 29233831
9. Sheard PW, Paine TJ (2010). Optimal contraction intensity during proprioceptive neuromuscular facilitation for maximal increase of range of motion.. Journal of strength and conditioning research. doi:10.1519/JSC.0b013e3181c50a0d PMID 20124794
10. Sheard PW, Smith PM, Paine TJ (2009). Athlete compliance to therapist requested contraction intensity during proprioceptive neuromuscular facilitation.. Manual therapy. doi:10.1016/j.math.2008.08.006 PMID 18996733
11. Konrad A, Stafilidis S, Tilp M (2017). Effects of acute static, ballistic, and PNF stretching exercise on the muscle and tendon tissue properties.. Scandinavian journal of medicine & science in sports. doi:10.1111/sms.12725 PMID 27367916
12. Szafraniec R, Chromik K, Poborska A, Kawczyński A (2018). Acute effects of contract-relax proprioceptive neuromuscular facilitation stretching of hip abductors and adductors on dynamic balance.. PeerJ. doi:10.7717/peerj.6108 PMID 30581683
13. Feland JB, Marin HN (2004). Effect of submaximal contraction intensity in contract-relax proprioceptive neuromuscular facilitation stretching.. British journal of sports medicine. doi:10.1136/bjsm.2003.010967 PMID 15273211
14. Kay AD, Husbands-Beasley J, Blazevich AJ (2015). Effects of Contract-Relax, Static Stretching, and Isometric Contractions on Muscle-Tendon Mechanics.. Medicine and science in sports and exercise. doi:10.1249/MSS.0000000000000632 PMID 25668401
15. Wanderley D, Lemos A, Moretti E, Barros MMMB, Valença MM, de Oliveira DA (2019). Efficacy of proprioceptive neuromuscular facilitation compared to other stretching modalities in range of motion gain in young healthy adults: A systematic review.. Physiotherapy theory and practice. doi:10.1080/09593985.2018.1440677 PMID 29474101
16. Mitchell UH, Myrer JW, Hopkins JT, Hunter I, Feland JB, Hilton SC (2009). Neurophysiological reflex mechanisms' lack of contribution to the success of PNF stretches.. Journal of sport rehabilitation. doi:10.1123/jsr.18.3.343 PMID 19827499
17. Osternig LR, Robertson RN, Troxel RK, Hansen P (1990). Differential responses to proprioceptive neuromuscular facilitation (PNF) stretch techniques.. Medicine and science in sports and exercise. PMID 2304405
18. Magnusson SP, Simonsen EB, Aagaard P, Dyhre-Poulsen P, McHugh MP, Kjaer M (1996). Mechanical and physical responses to stretching with and without preisometric contraction in human skeletal muscle.. Archives of physical medicine and rehabilitation. doi:10.1016/s0003-9993(96)90087-8 PMID 8607762
19. Behm DG, Alizadeh S, Daneshjoo A, Anvar SH, Graham A, Zahiri A, et al. (2023). Acute Effects of Various Stretching Techniques on Range of Motion: A Systematic Review with Meta-Analysis.. Sports medicine - open. doi:10.1186/s40798-023-00652-x PMID 37962709
20. Cayco CS, Labro AV, Gorgon EJR (2019). Hold-relax and contract-relax stretching for hamstrings flexibility: A systematic review with meta-analysis.. Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine. doi:10.1016/j.ptsp.2018.11.001 PMID 30423500
21. Mahieu NN, Cools A, De Wilde B, Boon M, Witvrouw E (2009). Effect of proprioceptive neuromuscular facilitation stretching on the plantar flexor muscle-tendon tissue properties.. Scandinavian journal of medicine & science in sports. doi:10.1111/j.1600-0838.2008.00815.x PMID 18627559
22. Konrad A, Gad M, Tilp M (2015). Effect of PNF stretching training on the properties of human muscle and tendon structures.. Scandinavian journal of medicine & science in sports. doi:10.1111/sms.12228 PMID 24716522
23. Higgs F, Winter SL (2009). The effect of a four-week proprioceptive neuromuscular facilitation stretching program on isokinetic torque production.. Journal of strength and conditioning research. doi:10.1519/JSC.0b013e3181a392c4 PMID 19620921
24. Minshull C, Eston R, Bailey A, Rees D, Gleeson N (2014). The differential effects of PNF versus passive stretch conditioning on neuromuscular performance.. European journal of sport science. doi:10.1080/17461391.2013.799716 PMID 23688197
25. Rees SS, Murphy AJ, Watsford ML, McLachlan KA, Coutts AJ (2007). Effects of proprioceptive neuromuscular facilitation stretching on stiffness and force-producing characteristics of the ankle in active women.. Journal of strength and conditioning research. doi:10.1519/R-20175.1 PMID 17530973
26. Handel M, Horstmann T, Dickhuth HH, Gülch RW (1997). Effects of contract-relax stretching training on muscle performance in athletes.. European journal of applied physiology and occupational physiology. doi:10.1007/s004210050268 PMID 9367279
27. Gomes TM, Simão R, Marques MC, Costa PB, da Silva Novaes J (2011). Acute effects of two different stretching methods on local muscular endurance performance.. Journal of strength and conditioning research. doi:10.1519/JSC.0b013e3181cc236a PMID 20647949
28. Belli I, Alghosi M, Kalayeh MB, Abdollahzadeh E, Heidari F, Azar RA, et al. (2026). How long should athletes with high range of motion demands stretch? Acute stretching durations for flexibility and performance: a systematic review.. Frontiers in physiology. doi:10.3389/fphys.2026.1881773 PMID 42539555
29. Medeiros DM, Martini TF (2018). Chronic effect of different types of stretching on ankle dorsiflexion range of motion: Systematic review and meta-analysis.. Foot (Edinburgh, Scotland). doi:10.1016/j.foot.2017.09.006 PMID 29223884
30. Rubini EC, Souza AC, Mello ML, Bacurau RF, Cabral LF, Farinatti PT (2011). Immediate effect of static and proprioceptive neuromuscular facilitation stretching on hip adductor flexibility in female ballet dancers.. Journal of dance medicine & science : official publication of the International Association for Dance Medicine & Science. PMID 22687658
31. Szafraniec R, Klich S, Koźlenia D (2026). Acute Effects of Static and Proprioceptive Neuromuscular Facilitation Stretching on the Ankle's Range of Motion and Postural Stability.. Journal of functional morphology and kinesiology. doi:10.3390/jfmk11020179 PMID 42200885
32. Khamwong P, Pirunsan U, Paungmali A (2011). A prophylactic effect of proprioceptive neuromuscular facilitation (PNF) stretching on symptoms of muscle damage induced by eccentric exercise of the wrist extensors.. Journal of bodywork and movement therapies. doi:10.1016/j.jbmt.2010.07.006 PMID 21943625

Every source the library cites

Changes

• October 23, 2026 First published.