ATHLETIC PUBALGIA: SYMPTOMS, CAUSES, PAIN AND TREATMENT

Groin pain is a common entity in athletes, particularly those engaged in sports that require specific use (or overuse) of lower abdominal muscles and the proximal musculature of the thigh (eg, soccer, ice hockey, Australian Rules football). Despite the high prevalence of groin pain in athletes, the cause of groin pain can be difficult to elucidate because of the complex local anatomy and the broad differential diagnosis.

 Chronic lower abdomen and groin pain is more prevalent in athletes involved in activities in which there are running, kicking, cutting movements, explosive turns and changes in direction, and rapid acceleration/deceleration. Soccer, ice hockey, and American football players tend to be most commonly affected in the United States. Other commonly involved sports include rugby, Australian Rules football, cricket, martial arts, basketball, baseball, field hockey, tennis, swimming, and long-distance running.
 

The most widely accepted theory of the pathogenesis is a disrupted rectus tendon attachment to the pubis and a weakened posterior inguinal wall. This develops as a result of an imbalance between the comparatively strong hip adductor muscles and the comparatively weaker lower abdominal muscles. The strong pull of the adductors, particularly against a fixed lower extremity, in the presence of relatively underconditioned abdominal muscles creates a shearing force across the hemipelvis, resulting in relative muscular overload with subsequent attenuation or tearing of the transversalis fascia and/or overlying musculature.
 

  Information extracted from:

-          Ellsworth, A. A., Zoland, M. P., & Tyler, T. F. (2014). Athletic pubalgia and associated rehabilitation. International journal of sports physical therapy, 9(6), 774.

-          Elattar, O., Choi, H. R., Dills, V. D., & Busconi, B. (2016). Groin injuries (athletic pubalgia) and return to play. Sports Health, 8(4), 313-323.   

 

SYMPTOMS

The pain may radiate into the adductor region, perineum, rectus muscles, inguinal ligament, and testicular area. The lower abdomen and groin pain is often aggravated by sudden acceleration, twisting and turning, cutting or kicking movements, sit-ups, coughing, or sneezing.

 The pain is activity related and generally resolves with rest. Taking time off from offending activities can lead to resolution of symptoms, but the hallmark is recurrence of the pain with resumption of sports. An acute presentation is much less common but has been reported with a trunk hyperextension, hip hyperabduction mechanism that can lead to partial or complete ruptures of the distal rectus abdominus/adductor aponeurosis.

  

Athletic pubalgia anatomy

PHYSICAL EXAMINATION

 The physical examination for athletic pubalgia begins with palpation of the potential sites of injury. Lower abdominal, adductor, and symphyseal pain to palpation is common in athletes; therefore, it is critical to determine whether the pain correlates with their symptoms. The abdominal obliques, transverses abdominis, and conjoined tendon/rectus abdominus should be palpated for tenderness.

 Occasionally symptoms can be reproduced by Valsalva maneuvers such as coughing and sneezing. The proximal adductor musculature (adductor longus, gracilis, pectineus) should also be palpated; resisted adduction in flexion and extension can be performed to elicit discomfort. Adductor tenderness has been reported in 36% of athletes with athletic pubalgia.

 The Consensus meeting suggested criteria for diagnosis of athletic pubalgia if at least 3 of the 5 following clinical signs are detectable:

 

(1) pinpoint tenderness over the pubic tubercle at the point of insertion of the conjoint tendon,

(2) palpable tenderness over the deep inguinal ring,

(3) pain and/or dilation of the external ring with no obvious hernia evident,

(4) pain at the origin of the adductor longus tendon, and

(5) dull, diffuse pain in the groin, often radiating to the perineum and inner thigh or across the midline.

 

DIFFERENTIAL DIAGNOSIS

 A thorough history and a physical examination is needed to differentiate groin strains from athletic pubalgia, osteitis pubis, hernia, hip-joint osteoarthrosis, rectal or testicular referred pain, piriformis syndrome or presence of a coexisting fracture of the pelvis or the lower extremities. Many of these diagnoses may exist in the active patient and present with similar symptoms and pain patterns.
 

ADDUCTOR STRAINS

 Adductor strains represent one of the most common groin injuries among athletes. Adductor strains accounted for 10% of all injuries in soccer players. Injuries usually occur at the musculotendinous junction but may also occur at the bone-tendon junction (enthesopathy), producing tenderness on deep palpation of the involved muscle and pain on resisted adduction.

 Although the diagnosis of these injuries is usually made clinically, ultrasound and magnetic resonance imaging may be used in the acute setting.

 

Adductor strain

OSTEITIS PUBIS

 Osteitis pubis is an isolated or repetitive insult to the pubic symphysis and surrounding structures, usually involving the adductor muscles or gracilis. It is usually seen in athletes with high-stress forces transferred through the pelvis and the pubic symphysis during kicking, rapid acceleration, deceleration, or sudden directional changes. These forces can cause stress reactions and a lytic response in the bone.

 The classic clinical presentation is pain in the pubic symphysis. There may be also pain in the proximal adductor, the lower abdominal muscles, perineal pain, and testicular or scrotal pain. Concomitant pathology must be ruled out such as adductor pathology, athletic pubalgia, and labral tears.

 The diagnosis of osteitis pubis is almost always made clinically, and radiographs are rarely helpful.
 

Osteitis pubis

CONSERVATIVE TREATMENT

 Groin pain from abdominal wall injury is common and often is self-limited and heals. In some cases, the injury becomes chronic and this subgroup of patients often requires surgery. Factors affecting treatment strategies include: timing, sports season length, prior conservative treatment, activity level, and degree of limitation in upcoming athletic events.

 

Conservative treatment for athletic pubalgia

 Ellsworth et al. proposed a protocol of conservative treatment for athletic pubalgia divided in different phases: 

Phase I (1-2 weeks)

·         Pain and edema control

·         Education regarding sitting, standing and supine posture and neutral spine

·         Transversus abdominis recruitment

·         Hip and lumbar spine mobilization to increase ROM (Grade I & II)

·         Gentle active stretching of hamstrings, adductors, quadriceps, iliopsoas, and lumbar spine.

·         Strengthening with the addition of little to no weight of the Transversus abdominis and side lying hip abduction and extension

Phase II (2-4 weeks)

·         Cardiovascular warm up bike or elliptical

·         Gait training on pelvic motion and timing for heel strike, mid-stance and push off

·         Continue TA (Transversus Abdominis) recruitment and strengthening

·         Achieve full to functional ROM for lumbar spine and increase hip ROM

·         Initiate static core strengthening with the ability to maintain neutral spine

·         Increase recruitment of hip and pelvic stabilization, emphasizing gluteals, TA and multifidus

·         Initiate functional strengthening starting with double leg exercise and progressing to single leg as pain and strength improves

·         Spine and hip mobilization addition of rotation (Grade II & III)

o    Do not progress to phase III without the following being met

-       Decreased pain with ADL’s less than 2/10

-       Full functional ROM of lumbar spine and hips

-       Ability to recruit and maintain TA contraction with standing and single

-       leg activity

-       No pain with ambulation

-       No trunk lateral motion (Trendelenberg) with ambulation and single leg activity

Phase III (4-6 weeks)

·         Cardiovascular warm up on bike or elliptical with higher speed and resistance, use of a treadmill with fast pace walking

·         Patient should demonstrate good pelvic stabilization and easy recruitment of the TA with ambulation

·         Gait training and pelvic proprioceptive neuromuscular function (PNF) patterns should continue and have a good motor pattern developing

·         Full to functional ROM should be achieved in the lumbopelvic area and hips, reduce any remaining restrictions

·         Dynamic core training with use of neutral spine during activity and use of unstable surfaces

·         Standing stabilization with resistance or balance disturbances added, progress from double to single leg functional activity

·         Continue with active stretching

·         Myofascial release and soft tissue work to any remaining restrictions

o  Do not progress to phase III without the following being met

-       No pain with ADL’s, ambulation, and fast paced walking

-       Full functional ROM of hips, pelvis, and lumbar spine

-       The ability to maintain spinal neutral with standing, sitting, walking, and single leg activity with added challenges of unstable surfaces or perturbations

-       Able to recognize and correct postural dysfunction when neutral spine is not maintained

Phase IV (Week 6-8)

·         Cardiovascular warm up should be sport/ recreational activity specific

·         ROM should be progressed to full if only functional was achieved

·         Active stretching interspersed with static stretching should be implemented

·         Strengthening should consist of concentric and eccentric strengthening in a functional, isotonic, isometric and isokinetic fashion.

·         Manual myofascial release and soft tissue mobilization to rectify any remaining restrictions

·         PNF pattern training of LE and UE/LE patterns

TEMPOROMANDIBULAR JOINT

The temporomandibular joint, or TMJ, is the joint formed at the top by the jaw and the temporal bone by the skull. This bone acts as a sliding hinge and can sometimes present problems due to the complexity of the movements it performs. Temporomandibular joint disorders can cause pain in the jaw joint and in the muscles that control jaw movement.

The temporomandibular joint combines rotation with sliding movements. The parts of the bones that interact in the joint are covered with cartilage, capsule, and are separated by a small disk that absorbs shock and accompanies movement.
 

TYPES OF TMJ DISORDERS

- Muscle pain that controls the movements of the jaw.
- Internal asymmetry caused by a displaced disc, by the subluxated jaw or by injuries of the condyle.
- Degenerative and inflammatory disorders of the TMJ.

Temporomandibular disk

 

THE SYMPTOMS

The following symptoms may indicate that you have a temporomandibular joint disorder:

- Jaw, face or neck pain, sensitivity to touch.
- Pain in one side of the head, which increases when teeth are clenched.
- Limited movement or blockage of the joint, making it difficult to open or close the jaw mouth.
- Pain and stiffness in the jaw muscles.
- Difficulty chewing. Ex: eat a sandwich, yawn, bite an apple.
- Ear pain in or around it and / or ringing or tinnitus.
- Pain when getting up in the morning that decreases throughout the day and that sometimes increases in the afternoon.

If you have answered “Yes” to any of these symptoms, we recommend that you go to physiotherapists specialized in Orofacial Pain and Craniomandibular Dysfunction, so that they can help you improve your quality of life.
 

Temporomandibular pain

CAUSES OF ATM DISORDERS

The exact cause of a person's TMJ disorder is often difficult to determine. Pain can be due to a combination of factors, such as genetics, arthritis, fractures, or an injury to the jaw.

However, the most frequent causes that can cause TMJ disorders are:

- Bruxism.
- Stress or anxiety.
- An injury to the jaw or TMJ.
- Certain wear on the disc or cartilage of the TMJ.
- A condition due to rheumatoid arthritis or gout.
- Other diseases that cause inflammation in the jaw.
 

Bruxism

RISK FACTOR'S

Some factors that can increase the risk of developing temporomandibular disorders are the following:

- Different types of arthritis, such as rheumatoid arthritis or osteoarthritis.
- Injury of the jaw.
- Long-term grinding or clenching of teeth (chronic).
- Bad postural habits: chewing gum, biting your nails, making strange gestures with your face, etc.
- Certain connective tissue diseases that cause problems that can affect the temporomandibular joint
 

PHYSIOTHERAPY AND TMJ

Physical therapy can help you restore natural jaw movement and reduce pain. Physiotherapy treatments for TMJ dysfunction may include:

- Active exercises and manual mobilizations (manual therapy): alone or in combination, they may be effective in the short term for increasing total vertical opening in patients with TMJ dysfunctions, resulting from acute disc displacement, acute arthritis, or acute or chronic myofascial syndrome. Often included in the treatment protocol is an exercise program to perform at home.

- Postural education: an advanced posture of the head when sitting can indicate that the cervical musculature is being put on tension, increasing the stress on the temporomandibular joint. As a consequence, the jaw muscles may be overworking at the closure of the mouth.

- Special treatments for pain: In addition to manual therapy, if the pain is severe, your physical therapist may decide to use treatments to reduce pain such as: transcutaneous electrical nerve stimulation (TENS), ultrasound, heat or cold in painful areas or tense.

- Radiofrequency: deeply relieves nerve endings and relaxes the muscles as far as our hands cannot reach.

- Acupuncture or dry needling of the masticatory and / or cervical muscles.

In most cases, the pain and discomfort associated with TMJ disorders are temporary and can be alleviated with non-surgical treatments. Surgery is usually the last resort after conservative measures have failed, but some people with TMJ disorders may benefit from surgical treatments.

Temporomandibular disorders can also cause a clicking or squeaking sensation when opening the mouth or chewing. But if there is no pain or limitation of movement associated with a snapping jaw, you probably don't need treatment for a temporomandibular disorder.
 

Temporomandibular physiotherapy

MULTIDISCIPLINARY

The treatment of disorders in the TMJ is multidisciplinary, since several health professionals may intervene. If the TMJ dysfunction is caused by tooth alignment problems, the physical therapist may refer you to a dentist or maxillofacial.

The swallowing or lingual movement also plays a fundamental role and it is necessary to refer it to the speech therapist.
 

PREVENTION OF ATM DYSFUNCTIONS

The general tips to decrease the probability of having temporomandibular pain are:

- Avoid stressful situations
- Avoid bad habits: nail biting, chewing gum, excess coffee and tea.
- Soft food.
- Do not clench your teeth.
- Perform some daily physical exercise.

SCIATICA RELATED TO HERNIATED DISC: SURGERY OR CONSERVATIVE TREATMENT

Herniated disc and sciatic

The column vertebrae are formed with 7 cervical vertebrae, 12 thoracic, 5 lumbars, 5 sacral and 3 coccygeus. Between each vertebra there is a disc formed with the annulus fibrosus and nucleus pulposus giving movement to the back, support and cushion the body´s weight.

The lower back is more prevalent to have a herniated disc having to support more weight than the other vertebrae and because it has a high mobility in flexion. The area of least resistance offered by the fibrous annulus is the posterior part. The nucleus is slightly delayed with respect to the geometric centre of the disc. This situation together with the bending movement causes the nucleus to exert more pressure on the back of the annulus.

Over the years, annulus wear down and nucleus can to go out. Usually, the herniated disc is not symptomatology but if nucleus affects the sciatic nerve we can feel symptoms. The most important symptom of sciatica is lumbosacral radicular leg pain that follows a dermatomal pattern radiating below the knee and into the foot and toes (1, 2).

Lumbar vertebrae

(Information extracted from: Jacobs, Wilco CH, et al. "Surgery versus conservative management of sciatica due to a lumbar herniated disc: a systematic review." European Spine Journal 20.4 (2011): 513-522)

The prevalence of sciatic symptoms reported in the literature varies considerably ranging from 1.6% in the general population to 43% in a selected working population (3). Although the prognosis is good in most patients (4), a substantial proportion (up to 30%) continues to have pain for 1 year or longer (5, 6).

 The goal of this study was to assess the effects of surgery versus conservative therapy (including epidural injections) for patients with sciatica due to lumbar disc herniation.

 In total, five studies were identified. One study compared early surgery with prolonged conservative care followed by surgery if needed (7); three studies compared surgery with usual conservative care (8,9,10), and one study compared surgery with epidural injections (11).
  

Early surgery versus prolonged conservative care

 1.       Relief of leg pain was faster for patients assigned to early surgery. Intention to treat analysis
showed statistically significant more leg pain relief in favour of early surgery as compared with prolonged conservative care at 3 months. There was no significant overall difference between the two groups in disability scores during the first year. The median time to recovery was 4 weeks for early surgery and 12 weeks for prolonged conservative treatment (7).
  

Surgery versus usual conservative care

 2.       Both patient and observer ratings demonstrated that discectomy was significantly better than conservative treatment at 1 year. After 1 year, 24 of the 66 patients (36%) in the conservative care group versus 39 of the 60 patients (65%) in the surgery group reported a good outcome. No significant differences in outcomes were reported at 4 and 10 years follow-up (9).


 3.       Overall, no significant differences were found for leg pain or back pain, and subjective disability throughout the 2 years of follow up. Visual analog scale leg pain scores, however, improved more rapidly in the discectomy group first 6 weeks (8).


 4.       Confirmed disc herniation showed that both the surgery as well as the conservative treatment group improved substantially over 2 years of leg pain and/or back pain (10).
  

Surgery versus epidural steroid injections

 5.       Patients undergoing discectomy had the most rapid decrease in their symptoms. The decrease in leg pain in the discectomy group was significantly greater than in the epidural steroid injection group at 3 and 6 month follow-up intervals, but not beyond 1 year. There were no significant differences between groups for back pain throughout the follow-up (11).

 

Epidural steroid injection

Conclusions

 In general, there is evidence that early surgery in patients with sciatica provides for a better short-term relief of leg pain as compared to prolonged conservative care. But no significant differences were found between surgery and usual conservative care in any of the clinical outcomes after 1 and 2 years.

  

Bibliography

 1. Valat JP, Genevay S, Marty M, Rozenberg S, Koes B (2010) Sciatica. Best Pract Res Clin Rheumatol 24:241–252

 2. van Tulder M, Peul W, Koes B (2010) Sciatica: what the rheumatologist needs to know. Nat Rev Rheumatol 6:139–145

 3. Konstantinou K, Dunn KM (2008) Sciatica: review of epidemiological studies and prevalence estimates. Spine (Phila Pa 1976) 33:2464–2472

 4. Legrand E, Bouvard B, Audran M, Fournier D, Valat JP (2007) Sciatica from disk herniation: medical treatment or surgery? Joint Bone Spine 74:530–535

 5. Vroomen PC, de Krom MC, Slofstra PD, Knottnerus JA (2000) Conservative treatment of sciatica: a systematic review. J Spinal Disord 13:463–469

 6. Weber H, Holme I, Amlie E (1993) The natural course of acute sciatica with nerve root symptoms in a double-blind placebocontrolled trial evaluating the effect of piroxicam. Spine (Phila Pa 1976) 18:1433–1438

 7. Peul WC, van Houwelingen HC, van den Hout WB, Brand R, Eekhof JA, Tans JT, Thomeer RT, Koes BW (2007) Surgery versus prolonged conservative treatment for sciatica. N Engl J Med 356:2245–2256

 8. Osterman H, Seitsalo S, Karppinen J, Malmivaara A (2006) Effectiveness of microdiscectomy for lumbar disc herniation: amrandomized controlled trial with 2 years of follow-up. Spine (Phila Pa 1976) 31:2409–2414

 9. Weber H (1983) Lumbar disc herniation. A controlled, prospective study with ten years of observation. Spine (Phila Pa 1976) 8:131–140

 10. Weinstein JN, Tosteson TD, Lurie JD, Tosteson AN, Hanscom B, Skinner JS, Abdu WA, Hilibrand AS, Boden SD, Deyo RA (2006) Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT): a randomized trial. JAMA 296:2441–2450

 11. Buttermann GR (2004) Treatment of lumbar disc herniation: epidural steroid injection compared with discectomy. A prospective, randomized study. J Bone Joint Surg Am 86-A:670–679

FIBROMYALGIA IMPROVES WITH STRENGTH TRAINING

Fibromyalgia (FM) is a chronic disease characterized by generalized skeletal muscle pain (1, 2), and other common symptoms include fatigue, sleep disorders, depression, and excessive anxiety (3–6). The pathogenesis of FM is still not well understood (7), and FM is considered by some researchers to be a neurobiological disease caused by abnormal processing of pain (8).

There is currently no cure for FM, but palliative treatments are available. One type of treatment is strength training (ST). The aim of this study was to analyze the effects of ST in the treatment of FM through a systematic review of experimental research. Twenty-two studies were included in the review. Women aged 18–65 years comprised the total sample and the main variables analyzed were pain, strength, muscular activity, functional capacity, fatigue, quality of life, and sleep. 

Information extracted from: (Andrade, A., de Azevedo Klumb Steffens, R., Sieczkowska, S. M., Peyré Tartaruga, L. A., & Torres Vilarino, G. (2018). A systematic review of the effects of strength training in patients with fibromyalgia: clinical outcomes and design considerations. Advances in Rheumatology, 58(1). doi:10.1186/s42358-018-0033-9). 

 

Results

 The analysis of the results revealed that ST reduced the symptoms of patients with FM, such as pain, fatigue, number of tender points, depression, and anxiety, with improved functional capacity and quality of life (9, 10, 11, 12, 13, 14, 15, 16), despite the different training protocols used.

 Pain

Pain was the most studied variable, showing a reduction after ST (11, 12, 17, 18, 19–21). No study reported increased pain after or during the intervention period

 Muscle Strength

With regard to muscle strength, increases between 33 and 63% were observed after 21 and 16 weeks (15, 22).

 Quality of life and Functionality

Studies analysing quality of life and functionality showed that ST is effective in improving these variables (23, 12, 24, 15, 16, 18).

 Depression

The most investigated psychological variable was depression. The studies of Jones et al. (18), Gavi et al. (12), and Assumpção et al. (25) showed that ST reduces depressive symptoms; however, the study of Ericsson et al. (10) did not find a significant difference after 15 weeks of intervention.

 Sleep Quality

We also analyzed the results related to sleep quality. Andrade et al. (9) found that sleep disorders were reduced after ST and that sleep correlated with pain. The results of Ericsson et al. (10) also disclosed that ST yielded better results than relaxation sessions in improving sleep quality. In addition, another important result is that patients with FM presented similar responses to those of healthy persons; thus, they recommended ST to assist in the treatment of patients.

  

Training Protocol

It was observed that there is no specific training protocol for patients with FM; thus, the researchers developed their own protocol.
 Intervention protocols should start at low intensity (40% of 1RM) and gradually increase the intensity. ST should be performed 2 or 3 times a week to exercise the main muscle groups.  The current studies showed that ST is a safe and effective method of improving the major symptoms of FM and can be used to treat patients with this condition.  

Example of Training Protocol, Rooks et al. (18)

The intervention was designed to gradually increase the volume and intensity of exercise a person performed, to involve all major muscle groups of the body, and to include all 3 aspects of fitness— cardiovascular endurance, muscle strength, and joint flexibility.
 The exercises began with a low volume of exercise performed at a low intensity, because of the expected lower levels of cardiovascular fitness and muscle strength reported in women with Fibromyalgia, and the lower threshold for postexercise muscle pain and fatigue seen in this population. Participants exercised for 60 minutes per session, 3 times per week for 20 weeks. The intervention was composed of 2 phases of exercise.

 The first phase (4 weeks) was performed in a pool, and focused on active range of motion of the body’s major joints. Movements were controlled single-joint motions.

 The second phase (16 weeks) involved land-based exercises for improving cardiovascular endurance, muscle strength, and joint range of motion. Each exercise session was divided into 3 sections—cardiovascular, strength training, and flexibility—and was always performed in the same order.

 - Cardiovascular exercises incorporated walking on a treadmill (Life Fitness), an elliptical device (Precor, Bothell, WA), and walking on a track.

 - Strength training exercises included static contractions for pelvic and lumbar spine stabilization, and dynamic movement of large muscles and multijoint actions: hip flexion/extension, knee extension/flexion, ankle plantar/dorsiflexion, shoulder flexion, extension, abduction and horizontal adduction and abduction, elbow flexion and extension, and trunk flexion and rotation.
Strength training exercises were performed using a combination of machines (Life Fitness), hand weights, and body weight. Subjects began with resistance levels they could do easily, and progressed in an 8-10-12-12 repetition format when appropriate.

 - Flexibility was developed using a complete range of motion during strength training movements, traditional stretches, and a flexibility device (Precor).

 The land-based exercise program was revised after 3 months to prevent boredom and reduce the chance of dropout.  

Conclusion

In conclusion, ST had positive effects on physical and psychological symptoms, in terms of reducing pain, the number of tender points, and depression, and improving muscle strength, sleep quality, functional capacity, and quality of life.  

Bibliography

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5. McDowell CP, Cook DB, Herring MP. The effects of exercise training on anxiety in fibromyalgia patients: a meta-analysis. Med Sci Sports Exerc. 2017; 49(9):1868–76 PubMed PMID: 28419024.Epub 2017/04/19.eng. 

6. Häuser W, Ablin J, Fitzcharles M-A, Littlejohn G, Luciano JV, Usui C, et al. Fibromyalgia. Nature reviews Disease primers. 2015;1:15022. 

7. Andrade A, Vilarino GT, Sieczkowska SM, Coimbra DR, Steffens RAK, Vietta GG. Acute effects of physical exercises on the inflammatory markers of patients with fibromyalgia syndrome: a systematic review. J Neuroimmunol. 2018;316:40–9. 

8. Sluka KA, Clauw DJ. Neurobiology of fibromyalgia and chronic widespread pain. 

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20. Larsson A, Palstam A, Lofgren M, Ernberg M, Bjersing J, Bileviciute-Ljungar I, et al. Resistance exercise improves muscle strength, health status and pain intensity in fibromyalgia-a randomized controlled trial. Arthritis Research & Therapy. 2015;17:15 PubMed PMID: WOS:000357248900001. English. 

21. Palstam A, Larsson A, Lofgren M, Ernberg M, Bjersing J, Bileviciute-Ljungar I, et al. Decrease of fear avoidance beliefs following person-centered progressive resistance exercise contributes to reduced pain disability in women with fibromyalgia: secondary exploratory analyses from a randomized controlled trial. Arthritis Research & Therapy. 2016;18 PubMed PMID: WOS:000376372300006. 

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25. Assumpção A ML, Yuan SL, Santos AS, Sauer J, Mango P, Marques AP. Muscle stretching exercises and resistance training in fibromyalgia: which is better? A three-arm randomized controlled trial. - PubMed - NCBI. 2017.