Pain Medicine, 0(0), 2020, 1–11
doi: 10.1093/pm/pnaa253
Review Article
Guzma
n-Pavo
n, MSc* Iva
n Cavero-Redondo, PhD,†,‡ Vicente Martınez-Vizcaıno, PhD, MD,†,§
Marıa Jose
n Ferna
ndez-Rodrıguez, MSc,† Sara Reina-Gutierrez, MSc,† and Celia Alvarez-Bueno,
Rube
PhD †,‡
*Universidad de Castilla-La Mancha, Faculty of Physiotherapy and Nursing, Toledo, Spain; †Universidad de Castilla la-Mancha, Health and Social
Research Center, Cuenca, Spain; ‡Universidad Polit
ecnica y Artıstica del Paraguay, Asunci
on, Paraguay; §Universidad Aut
onoma de Chile, Facultad de
Ciencias de la Salud, Talca, Chile
Correspondence to: Ivan Cavero-Redondo, PhD, Universidad de Castilla la-Mancha, Health and Social Research Center, Santa Teresa Jornet,
s/n, 16071 Cuenca, Spain. Tel: þ34-969179100; Fax: þ34-969179100; E-mail: ivan.cavero@uclm.es.
Funding sources: This study was funded by FEDER funds.
Conflicts of interest: No conflicts of interest were reported for this study.
Abstract
Objective. Myofascial pain syndrome is one of the primary causes of health care visits. In recent years, physical exer-
cise programs have been developed for the treatment of myofascial trigger points, but their effect on different outcomes has not been clarified. Thus, this study aimed to assess the effect of physical exercise programs on myofascial trigger points. Methods. A systematic search was conducted in Pubmed, Web of Science, and Scopus. Articles
analyzing the effect of physical exercise programs on pain intensity, pressure pain threshold, range of motion, and
disability were included. Risk of bias was assessed using the Cochrane RoB2 tool. The DerSimonian-Laird method
was used to compute the pooled effect sizes (ES) and their 95% confidence interval (95% CI) for pain intensity, pressure pain threshold, range of motion, and disability. Results. A total of 24 randomized controlled trials were included
in this systematic review and meta-analysis. The pooled ES were –0.47 (95% CI ¼ –0.61 to –0.33) for pain intensity,
0.63 (95% CI ¼ 0.31 to 0.95) for pressure pain threshold, 0.43 (95% CI ¼ 0.24 to 0.62) for range of motion, and –0.18
(95% CI ¼ –0.45 to 0.10) for disability. Conclusions. Physical exercise programs may be an effective approach in the
treatment of pain intensity, pressure pain threshold, and range of motion among patients with myofascial trigger
points.
Key words: Systematic Review; Myofascial Trigger Points; Exercise; Physical Activity
Introduction
Myofascial pain syndrome (MPS) is one of the most important causes of musculoskeletal pain [1] and one of the
most common causes of health care visits, absenteeism,
and disability [2]. MPS has a lifetime prevalence of up to
85% in the general population [2] and is the primary diagnosis for 85% of patients with chronic pain seen in
pain care centers [3]. Also, MPS prevalence is considerably high among specific pathologies, such as patellofemoral pain [4], lateral epicondylalgia [5], or chronic
tension-type headache [6].
The origin of MPS is located at the myofascial trigger
points (MTPs), which are hyperirritable regions placed in
the taut bands of skeletal muscles that become painful
when stimulated (e.g., compression or other mechanical
stimulations) and that can induce a typical pattern of referred pain, motor dysfunction, and autonomic responses
[7]. Other characteristic effects are increased tension, muscle shortening, restricted range of motion, impaired muscle
activation pattern, weakness, and increased muscle fatigue
[7–10]. Clinically, MTPs are classified as active or latent.
Both present similar physical findings, except that latent do
no elicit spontaneous symptoms and the referred pain is not
recognized as familiar to the patient [7].
The most effective methods to manage MPS are aimed
to treat MTPs, as MTPs are the main cause of generalized
C The Author(s) 2020. Published by Oxford University Press on behalf of the American Academy of Pain Medicine.
V
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1
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Effect of Physical Exercise Programs on Myofascial Trigger Points–
Related Dysfunctions: A Systematic Review and Meta-analysis
n-Pavo
n et al.
Guzma
2
However, evidence of the effectiveness of these PE
treatment strategies for MTPs is scarce and inconsistent.
Therefore, the objective of this systematic review and
meta-analysis was to assess the effect of PE interventions
on MTP dysfunctions, including pain intensity, pressure
pain threshold, range of motion, and disability.
Methods
Data Sources and Search Strategy
This systematic review and meta-analysis followed the
Cochrane Handbook [37] and is reported using the
PRISMA statement [38]. The protocol for this systematic
review was previously registered in PROSPERO with the
ID number CRD42020152988.
To identify all studies reporting the effects of PE programs on pain intensity, pressure pain threshold, range of
motion, and disability in patients with MTPs, a systematic search of the electronic databases PubMed, Scopus,
and Web of Science (WoS) from the inception of the
databases to February 2020 was conducted. The search
strategy included the following terms: “trigger points,”
“myofascial pain,” “myofascial pain syndrome,” “dry
needling,” “exercise,” “exercise therapy,” “physical
activity,” “trigger point therapy,” “physical therapy,”
“acupuncture,” and “physiotherapy.” The complete
search strategy for MEDLINE is presented in the
Supplementary Data. Additionally, the references of the
included studies were reviewed for any relevant studies.
Study Selection
Two reviewers (MJG-P and CA-B) independently
searched the databases. Disagreements were solved by
consensus or discussion with a third reviewer (VM-V).
Inclusion Criteria
The criteria for the inclusion of studies were as follows:
1) design: randomized controlled clinical trials (RCTs);
2) participants with MTPs; 3) type of intervention: any
type of PE intervention; 4) comparison: control or a nonPE intervention group; and 5) outcomes: pain intensity,
pressure pain threshold, range of motion, and disability.
Studies were excluded when 1) the study of MTPs was
not the main objective; 2) the PE program was based on
stretching exercises; and 3) studies were not written in
English, Spanish, French, or Italian.
Data Extraction
To examine the effect of the PE programs on MTPs outcomes, two reviewers (MJG-P and CA-B) independently
extracted the following data from each included article:
i) author and date of publication; ii) musculoskeletal
region evaluated, sample size by group, and mean age;
iii) intervention, dose, and length of the intervention; and
iv) outcomes measured. Disagreements in data collection
were settled by consensus.
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and referred pain in myofascial pain disorders [11].
Different techniques have been proposed for MTPs treatment. Evidence suggests that interventions such as dry
needling [12], light amplification by stimulated radiation
emission (LASER) [13], and manual therapy [14] are effective in treating MTPs, while evidence of the effectiveness of interventions such as myofascial release [15],
ultrasound (US) [16], transcutaneous electrical nerve
stimulation (TENS) [17], shock wave [18], and a combination of stretch and strengthening exercises [19] is not
as consistent.
Additionally, participating in physical exercise (PE)
programs for the treatment of pathologies closely related
to MTPs, such as osteoarthritis, osteoporosis, rheumatoid arthritis, chronic low-back pain, cervical pain,
or shoulder pain, has been increasingly recommended
[20–22]. More recently, exercise-based interventions
have been proposed due to their noninvasive, nonpharmacological, low-cost, and safety features. In addition to
their adaptability to patients’ characteristics and positive
association to pathologies, PE interventions have benefits
on physical and mental functions, such as quality of life,
sleep, anxiety, and depression [23]. Physical exercise programs may be an interesting add-on therapy during treatment and in combination with other techniques, such as
dry needling, which has been shown to be useful in the
treatment of MTPs (level of evidence 1A) [12] or with
other interventions, when dry needling is contraindicated
or the patient refuses this treatment. Moreover, exercisebased interventions are necessary to manage the consequences of MTPs such as impaired muscle activation patterns [8], weakness [9], and increased fatigability [10]
and, therefore, to promote a better response to treatment
and to restore the optimal state of the muscles.
Several types of PE may be prescribed for the treatment of MTPs, including stretching [24], aerobic and
strength exercises [25], and some types of combined exercises [26]. Several mechanisms have been proposed to explain the positive effects of PE on MTPs: 1) Aerobic and
isometric exercise may induce hypoalgesia and increase
pressure pain threshold by reducing central sensitivity,
resulting in multisegmental pain-inhibitory effects.
Additionally, exercise-induced hypoalgesia (EIH) has
been found to be larger in the exercising body part compared with remote sites, which indicates that local or segmental mechanisms could play an important role in EIH
[27–30]. 2) Muscular contraction could favor the drainage of sensitizing substances, which are presented in the
MTP environment, and therefore reduce the central and
peripheral sensitizations that cause local and/or referred
pain [31]. Moreover, aerobic exercise triggers the release
of anti-inflammatory cytokines, insulin-like growth factor–1 (IGF-1) and its binding protein (IGFBP-3), which
are involved in the neuroinflammatory response [32–34].
3) Finally, muscle contraction could cause localized
stretching of MTPs and, therefore, normalization of the
sarcomeres [35, 36].
Effect of Exercise on Myofascial Pain
Risk of Bias Assessment
Data Synthesis and Analysis
The pooled effect size (ES) estimates and their 95% confidence intervals (95% CI), using the DerSimonian-Laird
random-effects model [40], were calculated for each outcome (i.e., pain intensity, pressure pain threshold, range
of motion, and disability) using pre–post values. The clinical significance of the pooled ES was interpreted according to Cohen’s statements, suggesting that d ¼ 0.2 be
considered a “small” ES, 0.5 a “medium” ES, and 0.8 a
“large” ES. Pooled ES were estimated with negative values for pain intensity and disability and positive values
for pressure pain threshold and range of motion, both
meaning an effect in favor of the PE intervention.
Heterogeneity was assessed using the I2 statistic, and the
following values were used for interpretation: not important (0–40%), moderate (30–60%), substantial (50–
90%), and considerable (75–100%). Corresponding P
values were also considered [39].
Sensitivity analyses were performed excluding studies
one by one from the pooled estimates in order to evaluate
whether any particular study modified the original summary estimate. Finally, publication bias was estimated
using Egger’s test.
All statistical analyses were conducted using Stata 15
software.
Results
Study Selection
The initial search retrieved 5,906 studies, and after exclusion of nonrelevant studies, 42 studies were assessed for
eligibility. Of these, 24 RCTs met the inclusion criteria
and were included in this systematic review and metaanalysis (Supplementary Data).
Study Characteristics
The studies included in this systematic review and metaanalysis were published between 1986 and 2018. The
studies included a total of 1,221 participants, one study
[41] focused on men only, and two studies [42, 43] included women only. The mean age of participants ranged
from 15 to 76.5 years (Table 1).
The musculoskeletal regions most frequently evaluated were the cervical [26, 44–52], facial [42, 43, 53–58],
and shoulder areas [25, 26, 45, 46, 51, 52, 59, 60]. Other
regions evaluated were the scapular [47, 61], lower back
[52, 62], upper back [48], hip [41], thorax [52], and several regions of the upper limbs [52].
The studies included strength, aerobic, coordination, proprioception, and postural correction exercises. The frequency
of PE programs ranged from one to five times per week,
with a total duration ranging between one and 24 weeks.
The sessions lasted from 10 to 60 minutes per day.
According to MTP outcomes, 21 studies [26, 42–46,
48–62] assessed pain intensity, 15 [25,26,42,43,45,47–
49,54,55,58–62] pressure pain threshold, nine [41, 43,
49, 50, 53, 55, 58–60] range of motion, and six [42, 45,
46, 50, 59, 60] disability. Other parameters reported
were muscular tension [46, 61], functionality [59, 60],
quality of life [45, 51], depression [51, 62], anxiety [61],
fatigue, psychological status, emotional distress, and
sleep quality [53], posture [56], and kinesiophobia [62].
Risk of Bias Assessment
One study was assessed as low risk of bias, 15 as some
concerns, and eight as high risk of bias. Regarding each
domain specifically, the quality of studies was rated as
low risk for each domain as follows: 58.3% in the randomization process, 16.6% in the blinding of participants and researchers, 37.5% in the measurement of the
results, and 95.8% due to selection of the reported results
and missing outcome data (Supplementary Data).
Efficacy of PE on Pain Intensity, Pressure Pain
Threshold, Range of Motion, and Disability
The pooled ES estimates (Figures 1–4) for the effect of PE
programs were i) –0.47 (95% CI ¼ –0.61 to –0.33) for
pain intensity; ii) 0.63 (95% CI ¼ 0.31 to 0.95) for pressure pain threshold; iii) 0.43 (95% CI ¼ 0.24 to 0.62) for
range of motion; and iv) –0.18 (95% CI ¼ –0.45 to 0.10)
for disability. Heterogeneity was moderate for pain intensity (I2 ¼ 30.1%) and substantial for pressure pain
threshold (I2 ¼ 80.1%). There was no presence of heterogeneity for range of motion and disability.The sensitivity
analyses showed that results were not substantially modified when each study was removed from the analyses one
at a time for any MTPs outcome (Supplementary Data).
Finally, no publication bias was found as assessed by
Egger’s test or observed in funnel plot asymmetry
(Supplementary Data).
Discussion
The evidence supporting the effectiveness of exercise on
MTP-related dysfunctions is inconsistent. Our systematic
review and meta-analysis aimed to synthesize the evidence about the effect of PE programs on different MTP
dysfunctions. According to the most recent evidence [63],
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Two researchers (MJG-P and CA-B) independently
assessed the risk of bias of the RCTs included by applying
the Cochrane Collaboration’s tool for assessing risk of
bias (RoB2) [39]. Any disagreement was resolved by consensus or by discussion with a third reviewer (VM-V).
This tool assesses the risk of bias according to five
domains: bias derived from the randomization process,
bias due to deviations from planned interventions, bias
due to lack of results data, bias in the measurement of
the result, and bias in the notification of the results. Each
domain could score as low, moderate, or high risk of
bias. Finally, an overall risk of bias score was provided.
3
Region Evaluated
Cervical
Scapular
Facial
Shoulder
Facial
Cervical and shoulder
Cervical and shoulder
Cervical and shoulder
Acar and Yilmaz (2012)
Buttagat et al. (2016)
Carlson et al. (2001)
Cho et al. (2012)
Crockett et al. (1986)
Eftekharsadat et al. (2018)
FranC¸a et al. (2008)
Gam et al. (1998)
IG1: 18 (NR)
IG2: 22 (NR)
CG: 18 (NR)
IG1: 15 (3.75)
IG2: 15 (3.75)
IG3: 16 (3.69)
IG1: 30 (28)
IG2: 31 (27)
IG1: 7 (7)
IG2: 7 (7)
IG3: 7 (7)
IG1: 12 (NR)
IG2: 12 (NR)
IG3: 12 (NR)
IG1: 23 (NR)
IG2: 21 (NR)
IG: 18 (12)
CG: 18 (9)
IG1: 20 (17)
IG2: 20 (17)
CG: 20 (17)
No. by Group (Women)
Median: 39.5
Median: 42
Median: 38.5
38.0 6 10.0
30.0 6 13.0
33.0 6 15.0
IG1: US þ massage þ stretching
þ mobility and strength
exercises
IG2: sham US þ massage þ
stretching þ mobility
and strength exercises
CG: NT
IG1: acupuncture
IG2: stretching þ neck/upper
limbs strength exercises
IG3: combination
IG1: splint þ hot/cold applications þ postural correction þ
exercises for the jaw
IG2: muscle relaxation
IG3: TENS
IG1: acupuncture
IG2: acupuncture þ aerobic
exercise
>19 y
23.3 6 7.0
33.7 6 5.8
IG1: stabilization exercises
IG2: ESWT þ stabilization
exercises
IG3: ESWT
IG1: consuelling þ muscle relaxation þ proprioceptive training
þ physical activity þ diaphragmatic breathing
IG2: consuelling þ splint
IG1: hot pack þ US þ stretching
þ strengthening and postural
exercises
IG2: stretching þ strengthening
and postural exercises
CG: NT
IG1: stretching þ stabilization
exercises
CG: NT
Intervention
48.08 6 12.24
47.67 6 10.49
47.06 6 13.53
34.6
19.95 6 1.05
21.20 6 1.80
35.70 6 11.12
38.55 6 13.04
37.50 6 10.45
Age, Mean 6 SD, y
wk 1: 30 min
wk 2–4: 15 min
3/wk
4 wk
20 min
1–2 wk
10 wk
50 min
3/wk
10 wk
7/wk 8 wk
3/wk
4 wk
2 sessions in 3 wk
3 sets (10)
3/wk
4 wk
5/wk
2 wk
Length of Intervention
(continued)
Pain: VAS
PPT: algometer
Muscular tension: VAS
Anxiety: STAI
Pain: VAS, MPI
ROM: mm ruler
Psychological state: SCL-90-R
Fatigue: Likert-scale
Affective distress: MPI
Sleep quality: PSQI
Pain: VAS, CMS
PPT: algometer
ROM: CMS
Strength: CMS
Disability: NDI
Shoulder functionality: CMS
Pain: Likert-scale, MPQ
PPT: Likert scale
ROM: mm
Electromyographic activity:
EMG
Pain: VAS
PPT: algometer
Disability: NDI
Quality of life: QoL-SF36
Pain: VAS
Muscular tension: VAS
Disability: NDI-BR
Cervical flexor muscles recruitment patterns: bio-feedback
device
Number of MTPs: palpation
Pain: VAS, analgesic usage
PPT: palpation (0–3)
Pain: SF-MPQ
Connective tissue mobility: skinroll test
Outcome Measures
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Study
Table 1. Characteristics of the studies included in the systematic review and meta-analysis
4
n-Pavo
n et al.
Guzma
Region Evaluated
Facial
Cervical and scapular
Cervical and upper
back
Cervical
Cervical
Shoulder
Shoulder
Cervical and shoulder
Facial
Facial
Gavish et al. (2006)
Hanten et al. (1997)
Hanten et al. (2000)
Jagdhari et al. (2017)
Jyothirmai et al. (2015)
Lee et al. (2013)
Lee (2014)
Lugo et al. (2016)
Michelotti et al. (2000)
Michelotti et al. (2004)
IG: 26 (21)
CG: 23 (21)
IG: 19 (15)
CG: 13 (11)
IG1: 43 (36)
IG2: 43 (33)
IG3: 41 (35)
IG1: 5 (NR)
IG2: 5 (NR)
CG: 5 (NR)
IG1: 16 (9)
IG2: 16 (12)
IG1: 15 (NR)
IG2: 15 (NR)
IG1: 12 (NR)
IG2: 20 (NR)
IG3: 14 (NR)
40 (23)
60 (42)
IG: 10 (10)
CG: 10 (10)
No. by Group (Women)
26.4 6 8.4
32.6 6 13.7
27.4
42.6 6 9.7
37.7 6 11.8
37.2 6 11.1
25.2 6 0.8
71.2 6 05.3
24.3 6 0.5
48.1 6 13.2
47.7 6 10.7
18–35
15–60
30.6 6 9.3
29.9 6 9.2
27.1 6 10.1
27.3 6 5.9
Age, Mean 6 SD, y
IG1: occipital relaxation
IG2: active head exercises
CG: NT
IG1: IC þ stretching
IG2: active neck exercises
IG1: resisted jaw exercises þ
strengthening exercises of the
neck and upper back muscles
IG2: LASER
IG3: combination
IG1: INIT þ stretching þ neck
strength exercises
IG2: INIT
IG1: hot pack þ US þ TENS þ
muscle relaxation
þ shoulder and scapular stabilization exercises
IG2: hot pack þ US þ TENS
IG1: aerobic exercise (walk at
6.5 km/h)
IG2: strengthening exercises
CG: NT
IG1: hot pack þ US þ compression þ stretching
þ mobility and strength exercises
for the cervical and shoulder
girdle
IG2: lidocaine injection
IG3: combination
IG: consuelling þ massage þ
stretching þ
coordination and strength
exercises
CG: consuelling
IG: consuelling þ muscular relaxation with diaphragmatic
breathing þ massage þ heat
pads
þ stretching þ mandibular coordination exercises
CG: consuelling
IG: chewing exercise
CG: consuelling
Intervention
20
3/d
12 wk
6/d
7/wk
12 wk
3/wk
4 wk
40 min
15 min
14 sessions
4 wk
3 sets of 5 (each exercise)
2/d
5d
2/d
4 wk
wk 1–2: 10 min
wk 3–4: 15 min
wk 5–6: 20 min
wk 7–8: 30 min
3/d
8 wk
1 session
Length of Intervention
(continued)
Number of MTPs: palpation
Pain: VAS
ROM: mm
PPT: algometer
Pain: VAS, scale (0–4)
PPT: palpation (0–4)
Pain: VAS, SF-36
Quality of life: SF-36
Depression: PHQ-9
Pain: VAS
ROM: goniometer
Disability: NDI
Pain: VAS, CMS
PPT: algometer
ROM: CMS
Disability: NDI
Shoulder functionality: CMS
PPT: algometer
Pain: VAS, % of time in pain
PPT: algometer
Pain: VAS
PPT: palpation (0–3)
ROM: mm
PPT: algometer
Pain: VAS, PRS
PPT: palpation (0–3)
Disability: disability scale
Outcome Measures
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Study
Table 1. continued
Effect of Exercise on Myofascial Pain
5
Facial
Forearm, arm, cervical, fingers, lumbar,
hands, shoulders,
wrists, thorax
Hip
Low back
Facial
Facial
Mulet et al. (2007)
Pereira et al. (2013)
Tüzün et al. (2017)
Van Grootel et al. (2017)
Wright et al. (2000)
IG: 30 (26)
CG: 30 (25)
IG1: 37 (95)
IG2: 35 (91)
IG1: 18 (8)
IG2: 16 (12)
IG1: 33 (NR)
IG2: 33 (NR)
CG: 33 (NR)
IG: 44 (NR)
CG: 17 (NR)
IG: 20 (19)
CG: 22 (21)
No. by Group (Women)
32.7
30.8
31.4 6 9.6
29.0 6 9.6
50.1 6 11.8
50.9 6 12.5
20 6 1.5
20 6 2.0
20 6 2.0
28.7 6 8.8
27.8 6 7.4
25.1 6 2.3
23.4 6 2.1
Age, Mean 6 SD, y
IG1: consuelling þ relaxation þ
massage þ stretching þ postural, proprioceptive and
strength exercises
IG2: splint
IG: consuelling þ postural
exercises
CG: consuelling
IG1: IC þ stretching
IG2: IC þ stretching þ medicine
ball exercise
CG: NT
IG1: dry needling þ massage
IG2: hot pack þ TENS þ US þ
stretching þ strength exercises
in abdomen and back muscles
IG: consuelling þ muscular relaxation with diaphragmatic
breathing þ postural, active
and control exercisesCG:
consuelling
IG: stretching þ muscular endurance þ relaxation þ massage
þ group dynamicCG: NT
Intervention
30 min
4 wk
2–3/wk
9 wk
3 sets of 10 (each exercise)
2/d
3 wk
50 each side
10 min 2/d
5/wk
24 wk
6 (each exercise)
6/d
4 wk
Length of Intervention
Pain: SSI
PPT: algometer
ROM: mm
Number of MTPs: palpation
Pain: SF-MPQ, VAS
PPT: palpation (0–2)
Depression: BDI
Kinesiophobia: TSK
Pain: VAS
ROM: Modified Thomas Test
Measures of biomechanics and
golf performance
Pain: Trigger Points Test
questionnaire
Pain: NGRS, VRS
Posture: distance shoulder-to-ear,
neck angle, cranial angle
Outcome Measures
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BDI ¼ Beck Depression Inventory; C-CFT ¼ cranio-cervical flexion test; CG ¼ control group; CMS ¼ Constant-Murley Scale; EMG ¼ electromyography; ESWT ¼ extracorporeal shock wave therapy; IC ¼ ischemic compression; IG ¼ intervention group; INIT ¼ integrated neuromuscular inhibitory technique; LASER ¼ light amplification by stimulated emission of radiation; MPI ¼ Multidimensional Pain Inventory; MPQ ¼ McGill Pain
Questionnaire; MTP ¼ myofascial trigger point; NDI ¼ Neck Disability Index; NDI-BR ¼ Brazilian Portuguese version of the Neck Disability Index; NGRS ¼ numerical graphic rating scale; NR ¼ not reported; NT ¼ no treatment; PHQ-9 ¼ Patient Health Questionnaire; PPT ¼ pressure pain threshold; PRS ¼ Pain Relief Scale; PSQI ¼ Pittsburgh Sleep Quality Index; QoL-SF36 ¼ Quality of Life SF-36 Questionnaire; ROM ¼ range of movement;
SCL-90-R ¼ Revised Symptom Checklist–90; SF36 ¼ SF-36 Questionnaire; SF-MPQ ¼ Short-Form McGill Pain Questionnaire; SSI ¼ Symptom Severity Index; STAI ¼ State Anxiety Inventory; TENS ¼ transcutaneous electrical
nerve stimulation; TSK ¼ Tampa Scale of Kinesiophobia; US ¼ ultrasound; VAS ¼ visual analog scale; VRS ¼ verbal rating scale.
Quinn et al. (2016)
Region Evaluated
Study
Table 1. continued
6
n-Pavo
n et al.
Guzma
Effect of Exercise on Myofascial Pain
7
the findings of this systematic review and meta-analysis
support that PE is effective in reducing pain intensity and
increasing the pressure pain threshold and range of motion; however, no evidence on reducing disability in
patients with MTPs was observed.
PE is usually linked with stretching, aerobic, and
strength exercises. However, other types of exercise have
been proposed, such as postural, proprioceptive, coordination, and stabilization interventions. It has been postulated
that postural changes are one of the factors involved in the
development and perpetuation of MTPs by altering the normal anatomic relationships [56]. Specific proprioceptive
training regimes are designed to target the deep muscles as
they have the highest density of receptors and are known to
have a specific role in reflex and central connections to the
vestibular, visual, and postural control systems.
Additionally, coordination exercises have been advocated
for addressing impaired neuromuscular control [64].
Finally, stabilization exercises are proposed to enhance the
strength of the postural muscles, stabilizing the muscles and
increasing the stability of the relevant joints [60]. Despite
their potentially interesting effects, studies assessing the effectiveness of these techniques in the treatment of MTPs are
scarce, so further studies are needed to show the efficacy of
these approaches in the treatment of MTPs.
Our results show that PE is effective in reducing pain
intensity and increasing the pressure pain threshold.
These findings are in line with those of previous studies
reporting exercise benefits as compared with no intervention [61] or interventions such as support and encouragement [42], LASER [49], TENS [43], or lidocaine
injection [51]. Several pathophysiological mechanisms
have been proposed to explain the positive effect of PE
on MTPs, such as the counteracting effect of the local ischemia of MTPs caused by the sustained contraction of
sarcomeres, which stimulates the release of the sensitizing
substances that produce nociception [7]. The muscular
contraction performed during PE could favor the blood
supply and drainage of sensitizing substances present in
the MTP environment, and therefore reduce the central
and peripheral sensitizations that cause local and/or referred pain [11]. Finally, the abnormal tension of the taut
bands where MTPs are located is responsible for the frequent existence of mobility restriction [65]. Muscle contraction could cause localized stretching of MTPs and,
thereby, normalization of the sarcomeres [19].
Conversely, although all the studies including disability as an outcome reported a positive effect on reducing
disability [24, 27, 28, 32, 41, 42], the pooled estimates
did not achieve statistical significance. As pain is one of
Downloaded from https://academic.oup.com/painmedicine/advance-article/doi/10.1093/pm/pnaa253/5917822 by University of New England user on 12 October 2020
Figure 1. Forest plot for the effect of physical exercise on pain intensity.
8
Figure 3. Forest plot for the effect of physical exercise on range of motion.
Downloaded from https://academic.oup.com/painmedicine/advance-article/doi/10.1093/pm/pnaa253/5917822 by University of New England user on 12 October 2020
Figure 2. Forest plot for the effect of physical exercise on pressure pain threshold.
n-Pavo
n et al.
Guzma
Effect of Exercise on Myofascial Pain
9
the most important causes of disability in MPS patients,
the lack of data on the outcome of included studies
reporting high ES on pain reduction may be behind the
observed lack of statistical power. The apparent mismatch between the effect of PE interventions on pain intensity and disability could also be due to the
biopsychosocial characteristics of patients, such as gender, occupational factors, anxiety, and fear, which may
act as mediators of effect modifiers on the relationship
between pain and functional capacity [65]. Moreover,
longer interventions and follow-up periods may be
needed to observe changes in patients’ disability perception. This is because the consequences of pain and disability, such as depression, may have a negative influence
on this perception and may continue after improvements
in pain or pressure pain threshold.
Some limitations of this study should be acknowledged. First, the selection of studies addressing the assessment of the effectiveness of PE in the treatment of MTPs
may be incomplete, as gray literature sources were not included. Second, the diagnosis of MTPs was not always
clear due to the lack of a standard criterion and because
the identification of taut bands and MTPs requires experience among examiners. To minimize this limitation,
MTPs were considered as a primary condition in all studies, excluding other clinical manifestations commonly
observed in patients with MTPs (e.g., fibromyalgia).
Third, although the results showed favorable effects of
PE programs on MTP-related dysfunctions, they should
be interpreted with caution considering the small number
of studies, the heterogeneity, and the large proportion of
studies assessed as “high risk of bias” (33.3%) or
“unclear risk of bias” (62.5%). Fourth, the quality of our
analysis is limited by the quality of the underlying data.
Finally, the adequate prescription of a PE program in the
treatment of MTPs should be personalized considering
the individual characteristics of the patient and associated pathologies.
Conclusions
PE may be an effective therapeutic strategy for reducing
pain intensity while increasing pressure pain threshold
and range of motion in individuals with MTPs. Future
studies should investigate the effects of PE programs on
other clinical outcomes, such as quality of life, and use
standard criteria for the diagnosis of MTPs.
Additionally, a detailed description of the PE intervention’s characteristics for the treatment of MTPs is necessary in order to better adapt these programs to the
patients’ characteristics and possible associated
pathologies.
Supplementary Data
Supplementary data are available at Pain Medicine online.
References
1. Gerwin RD. Diagnosis of myofascial pain syndrome. Phys Med
Rehabil Clin N Am 2014;25(2):341–55.
2. Fleckenstein J, Zaps D, Rüger LJ, et al. Discrepancy between
prevalence and perceived effectiveness of treatment methods in
myofascial pain syndrome: Results of a cross-sectional, nationwide survey. BMC Musculoskelet Disord 2010;11(1):32.
3. Fishbain DA, Goldberg M, Meager BR, Steele R, Rosomoff H.
Male and female chronic pain patients characterized by DSM-III
diagnostic criteria. Pain 1986;26:181–97.
4. Roach S, Sorenson E, Headley B, San Juan JG. Prevalence of
myofascial trigger points in the hip in patellofemoral pain. Arch
Phys Med Rehabil 2013;94(3):522–6.
Downloaded from https://academic.oup.com/painmedicine/advance-article/doi/10.1093/pm/pnaa253/5917822 by University of New England user on 12 October 2020
Figure 4. Forest plot for the effect of physical exercise on disability.
10
22. Pedersen BK, Saltin B. Exercise as medicine—evidence for prescribing exercise as therapy in 26 different chronic diseases.
Scand J Med Sci Sport 2015;25:1–72.
23. US Department of Health and Human Services. Physical Activity
Guidelines for Americans. 2nd ed. Washington, DC: US
Department of Health and Human Services; 2018.
24. Edwards J, Knowles N, Edwards J. Superficial dry needling and
active stretching in the treatment of myofascial pain. Acupunct
Med 2003;21(3):80–6.
25. Lee HS. The effects of aerobic exercise and strengthening exercise on pain pressure thresholds. J Phys Ther Sci 2014;26
(7):1107–11.
26. Gam AN, Warming S, Larsen LH, et al. Treatment of myofascial
trigger-points with ultrasound combined with massage and exercise: A randomised controlled trial. Pain 1998;77(1):73–9.
27. Drury DG, Stuempfle K, Shannon R, Miller J. An investigation
of exercise-induced hypoalgesia after isometric and cardiovascular exercise. J Exerc Physiol Online 2004;7:1–5.
28. Koltyn KF, Brellenthin AG, Cook DB, Sehgal N, Hillard C.
Mechanisms of exercise-induced hypoalgesia. Psychiatrie 2018;
22:33–8.
29. Vaegter HB, Handberg G, Graven-Nielsen T. Similarities between exercise-induced hypoalgesia and conditioned pain modulation in humans. Pain 2014;155(1):158–67.
30. Ristic D, Ellrich J. Exercise-induced hypoalgesia differentially
affects deep pain, cutaneous pain and innocuous somatosensation. Acta Physiol 2015;213:63–4.
31. Shah JP, Gilliams EA. Uncovering the biochemical milieu of
myofascial trigger points using in vivo microdialysis: An application of muscle pain concepts to myofascial pain syndrome. J
Bodyw Mov Ther 2008;12(4):371–84.
32. Haydar ZR, Blackman MR, Tobin JD, Wright JG, Fleg JL. The
relationship between aerobic exercise capacity and circulating
IGF-1 levels in healthy men and women. J Am Geriatr Soc 2000;
48(2):139–45.
33. Irwin ML, Varma K, Alvarez-Reeves M, et al. Randomized controlled trial of aerobic exercise on insulin and insulin-like growth factors in breast cancer survivors: The Yale Exercise and Survivorship
Study. Cancer Epidemiol Biomarkers Prev 2009;18(1):306–13.
34. Ortega E, Garcıa JJ, Bote ME, et al. Exercise in fibromyalgia and
related inflammatory disorders: Known effects and unknown
chances. Exerc Immunol Rev 2009;15:42–65.
35. Jafri MS. Mechanisms of myofascial pain. Int Sch Res Notices
2014;2014.
36. Majlesi J, Unalan H. Effect of treatment on trigger points. Curr
Pain Headache Rep 2010;14(5):353–60.
37. Higgins JP, Green SE. Cochrane Handbook for Systematic
Reviews of Interventions. Version 5.1.0. Chichester, UK: Wiley
Publication; 2011.
38. Liberati A, Altman DG, Tetzlaff J, et al. The PRISMA statement
for reporting systematic reviews and meta-analyses of studies
that evaluate health care interventions: Explanation and elaboration. J Clin Epidemiol 2009;62(10):e1–34.
39. Higgins P, Savovic H, Page M, Sterne J. Revised Cochrane riskof-bias tool for randomized trials (RoB2). 2019. https://methods.
cochrane.org/bias/resources/rob-2-revised-cochrane-risk-biastool-randomized-trials (accessed 5 May 2020).
40. DerSimonian R, Laird N. Meta-analysis in clinical trials.
Control Clin Trials 1986;7(3):177–88.
41. Quinn SL, Olivier B, Wood WA. The short-term effects of trigger
point therapy, stretching and medicine ball exercises on accuracy
and back swing hip turn in elite, male golfers: A randomised controlled trial. Phys Ther Sport 2016;22:16–22.
42. Gavish A, Winocur E, Astandzelov-Nachmias T, Gazit E. Effect
of controlled masticatory exercise on pain and muscle
Downloaded from https://academic.oup.com/painmedicine/advance-article/doi/10.1093/pm/pnaa253/5917822 by University of New England user on 12 October 2020
5. Fernandez-Carnero J, Fern
andez-de-las-Pe~
nas C, de la LlaveRinc
on AI, Ge H, Arendt-Nielsen L. Prevalence of and referred
pain from myofascial trigger points in the forearm muscles in
patients with lateral epicondylalgia. Clin J Pain 2007;23:353–
60.
6. Coupp C, Torelli P, Fuglsang-Frederiksen A, Andersen KV,
Jensen R. Myofascial trigger points are very prevalent in patients
with chronic tension-type headache. Clin J Pain 2007;23(1):23–
7.
7. Simons D, Travell J, Simons L. Travell & Simons’ Myofascial
Pain and Dysfunction. The Trigger Point Manual. Vol. 1. Upper
Half of Body. 2nd ed. London: Williams & Wilkins; 1999.
8. Lucas KR, Rich PA, Polus BI. Muscle activation patterns in the
scapular positioning muscles during loaded scapular plane elevation: The effects of latent myofascial trigger points. Clin
Biomech 2010;25(8):765–70.
9. Celik D, Yeldan I. The relationship between latent trigger point
and muscle strength in healthy subjects: A double-blind study. J
Back Musculoskelet Rehabil 2011;24(4):251–6.
10. Ge H, Arendt-nielsen L, Madeleine P. Accelerated muscle fatigability of latent myofascial trigger points in humans. Pain Med
2012;13(7):957–64.
11. Ahmed S, Khattab S, Haddad C, Babineau J, Furlan A,
Kumbhare D. Effect of aerobic exercise in the treatment of myofascial pain: A systematic review. J Exerc Rehabil 2018;14
(6):902–10.
12. Kietrys DM, Palombaro KM, Azzaretto E, Hubler R, Schaller B,
Schlussel JM, Tucker M. Effectiveness of dry needling for upperquarter myofascial pain: A systematic review and meta-analysis.
J Orthop Sports Phys Ther 2013;43(9):620–34.
13. Munguia FM, Jang J, Salem M, Clark GT, Enciso R. Efficacy of
low-level laser therapy in the treatment of temporomandibular
myofascial pain: A systematic review and meta-analysis. J Oral
Facial Pain Headache 2018;32(3):287–97.
14. Charles D, Hudgins T, MacNaughton J, Newman E, Tan J,
Wigger M. A systematic review of manual therapy techniques,
dry cupping and dry needling in the reduction of myofascial pain
and myofascial trigger points. J Bodyw Mov Ther 2019;23
(3):539–46.
15. Laimi K, M€akil€a A, B€
arlund E, et al. Effectiveness of myofascial
release in treatment of chronic musculoskeletal pain: A systematic review. Clin Rehabil 2018;32(4):440–50.
16. Xia P, Wang X, Lin Q, Cheng K, Li X. Effectiveness of ultrasound therapy for myofascial pain syndrome: A systematic review and meta-analysis. J Pain Res 2017;10:545-55.
17. Ahmed S, Haddad C, Subramaniam S, Khattab S, Kumbhare D.
The effect of electric stimulation techniques on pain and tenderness at the myofascial trigger point: A systematic review. Pain
Med 2019;20(9):1774–88.
18. Yoo JI, Oh MK, Chun SW, Lee SU, Lee CH. The effect of focused extracorporeal shock wave therapy on myofascial pain
syndrome of trapezius: A systematic review and meta-analysis.
Medicine 2020;99(7):e19085.
19. Mata Diz JB, de Souza J, Leopoldino AAO, Oliveira VC.
Exercise, especially combined stretching and strengthening exercise, reduces myofascial pain: A systematic review. J Physiother
2017;63(1):17–22.
20. Smidt N, de Vet HCW, Bouter LM, Dekker J. Effectiveness of
exercise therapy: A best-evidence summary of systematic
reviews. Aust J Physiother 2005;51(2):71–85.
21. van Middelkoop M, Rubinstein SM, Verhagen AP, Ostelo RW,
Koes BW, van Tulder MW. Exercise therapy for chronic nonspecific low-back pain. Best Pract Res Clin Rheumatol 2010;24
(2):193–204.
n-Pavo
n et al.
Guzma
Effect of Exercise on Myofascial Pain
43.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
temporomandibolari. Studio clinico controllato. Minerva
Stomatol 2000;49:541–8.
Michelotti A, Steenks MH, Farella M, Parisini F, Cimino R,
Martina R. The additional value of a home physical therapy regimen versus patient education only for the treatment of myofascial pain of the jaw muscles: Short-term results of a randomized
clinical trial. J Orofac Pain 2004;18:114–25.
Mulet M, Decker KL, Look JO, Lenton PA, Schiffman EL. A
randomized clinical trial assessing the efficacy of adding 6 x 6
exercises to self-care for the treatment of masticatory myofascial
pain. J Orofac Pain 2007;21:318–28.
Van Grootel RJ, Buchner R, Wismeijer D, Van Der Glas HW.
Towards an optimal therapy strategy for myogenous TMD,
physiotherapy compared with occlusal splint therapy in an RCT
with therapy-and-patient-specific treatment durations. BMC
Musculoskelet Disord 2017;18(1):76.
Wright EF, Domenech MA, Fischer JR. Usefulness of posture
training for patients with temporomandibular disorders. J Am
Dent Assoc 2000;131(2):202–10.
Cho YS, Park SJ, Jang SH, Choi YC, Lee JH, Kim JS. Effects of
the combined treatment of extracorporeal shock wave therapy
(ESWT) and stabilization exercises on pain and functions of
patients with myofascial pain syndrome. J Phys Ther Sci 2012;24
(12):1319–23.
Lee JH, Park SJ, Na SS. The effect of proprioceptive neuromuscular facilitation therapy on pain and function. J Phys Ther Sci
2013;25(6):713–6.
Buttagat V, Taepa N, Suwannived N, Rattanachan N. Effects of
scapular stabilization exercise on pain related parameters in
patients with scapulocostal syndrome: A randomized controlled
trial. J Bodyw Mov Ther 2016;20(1):115–22.
€ Malkoç M.
Tüzün EH, Gildir S, Angın E, Tecer BH, Dana KO,
Effectiveness of dry needling versus a classical physiotherapy
program in patients with chronic low-back pain: A single-blind,
randomized, controlled trial. J Phys Ther Sci 2017;29(9):1502–
9.
Kim W, Hur M-H. Effect of resistance exercise program for
middle-aged women with myofascial pain syndrome on shoulder
pain, angle of shoulder range of motion, and body composition
randomized controlled trial. RCT 2020;50(2):286–97.
Izquierdo T, Pecos-Martin D, Girbes E, et al. Comparison of
cranio-cervical flexion training versus cervical proprioception
training in patients with chronic neck pain: A randomized controlled clinical trial. J Rehabil Med 2016;48(1):48–55.
Mayoral O, Salvat I. Fisioterapia Invasiva Del Sındrome de
Dolor Miofascial. Manual de Punci
on Seca de Puntos Gatillo.
Madrid: Medica Panamerica; 2017.
Downloaded from https://academic.oup.com/painmedicine/advance-article/doi/10.1093/pm/pnaa253/5917822 by University of New England user on 12 October 2020
44.
performance in myofascial pain patients: A pilot study. Cranio
2006;24(3):184–90.
Crockett DJ, Foreman ME, Alden L, Blasberg B. A comparison
of treatment modes in the management of myofascial pain dysfunction syndrome. Biofeedback Self Regul 1986;11(4):279–91.
€ Effects of different physiotherapy applicaAcar B, Yilmaz OT.
tions on pain and mobility of connective tissue in patients with
myofascial pain syndrome. J Back Musculoskelet Rehabil 2012;
25(4):261–7.
Eftekharsadat B, Porjafar E, Eslamian F, et al. Combination of
exercise and acupuncture versus acupuncture alone for treatment
of myofascial pain syndrome: A randomized clinical trial. J
Acupunct Meridian Stud 2018;11(5):315–22.
França DLM, Senna-Fernandes V, Cortez CM, Jackson MN,
Bernardo-Filho M, Guimar~
aes M. Tension neck syndrome treated
by acupuncture combined with physiotherapy: A comparative clinical trial (pilot study). Complement Ther Med 2008;16(5):268–77.
Hanten W, Barret M, Gillespie-Plesko M, Jump K, Olson S.
Effects of active head retraction with retraction/extension and occipital release on the pressure pain threshold of cervical and scapular trigger points. Physiother Theory Pract 1997;13(4):285–91.
Hanten WP, Olson SL, Butts NL, Nowicki AL. Effectiveness of a
home program of ischemic pressure followed by sustained
stretch for treatment of myofascial trigger points. Phys Ther
2000;80(10):997–1003.
Smriti Jagdhari B, Mukta M, Golhar Saket A, Golhar AV.
Therapeutic evaluation of cervical dysfunction in patients with
myofascial pain dysfunction syndrome: A prospective study. J
Contemp Dent Pract 2017;18(7):601–6.
Jyothirmai B, Kumar, S Raghavkrishna, K Madhavi S. K.
Effectiveness of integrated neuromuscular inhibitory technique
(INIT) with specific strength training exercises in subjects with
upper trapezius trigger. Int J Physiother 2015;2:759–63.
Lugo LH, Garcıa HI, Rogers HL, Plata JA. Treatment of myofascial pain syndrome with lidocaine injection and physical therapy,
alone or in combination: A single blind, randomized, controlled
clinical trial. BMC Musculoskelet Disord 2016;17(1):101.
Pereira C, L
opez RFA, Vilarta R. Effects of physical activity programmes in the workplace (PAPW) on the perception and intensity of musculoskeletal pain experienced by garment workers.
Work 2013;44(4):415–21.
Carlson CR, Bertrand PM, Ehrlich AD, Maxwell AW, Burton
RG. Physical self-regulation training for the management of temporomandibular disorders. J Orofac Pain 2001;15:47–55.
Michelotti A, Parisini F, Farella M, Cimino R, Martina R.
Fisioterapia
muscolare
in
pazienti
con
disordini
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