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Stretching exercises combined with ischemic compression in pectoralis minor muscle with latent trigger points: A single-blind, randomized, controlled pilot trial

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Complementary Therapies in Clinical Practice 38 (2020) 101080

Available online 18 December 2019

1744-3881/© 2019 Elsevier Ltd. All rights reserved.

Stretching exercises combined with ischemic compression in pectoralis

minor muscle with latent trigger points: A single-blind, randomized,

controlled pilot trial

Tansu Birinci

a,b

, Rustem Mustafaoglu

c

, Ebru Kaya Mutlu

c,*

, Arzu Razak Ozdincler

d aIstanbul University-Cerrahpasa, Institute of Graduate Studies, Division of Physiotherapy and Rehabilitation, Istanbul, Turkey

bIstanbul Medeniyet University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Istanbul, Turkey cIstanbul University-Cerrahpasa, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Istanbul, Turkey dBiruni University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Istanbul, Turkey

A R T I C L E I N F O Keywords:

Pain threshold Pectoralis minor

Proprioceptive neuromuscular facilitation stretching

Respiratory pressure Spirometer

A B S T R A C T

Background and purpose: Latent trigger points (LTrPs) in the pectoralis minor (PM) muscle lead to muscle tightness. This study aimed to investigate which type of stretching exercise used after ischemic compression (IC) was more effective on LTrPs in the PM muscle.

Materials and methods: Forty participants with PM muscle tightness and an LTrP in the PM muscle were divided among groups 1 (IC with modified contract-relax proprioceptive neuromuscular facilitation (PNF) stretching), 2 (IC with static stretching), 3 (IC with myofascial release) and 4 (no intervention). The PM muscle index (PMI), PM length (PML), rounded shoulder posture, pressure pain threshold, pulmonary function, and maximal respi-ratory pressure were evaluated.

Results: Improvement in the PMI and PML was found immediately after the intervention in groups 1 and 3 compared with baseline (p ¼ 0.01). The overall group-by-time interaction in the repeated measures analysis of variance was significant for the PMI in favor of Group 1 (F1, 36 ¼3.53, p ¼ 0.02).

Conclusion: IC may be followed by contract-relax PNF stretching to increase the length of PM muscle with LTrPs.

1. Introduction

A myofascial trigger point (MTrP), which can be classified as an active trigger point (ATrP) or a latent trigger point (LTrP), is a hyperirritable spot located in a palpable, taut band of skeletal muscle that is painful upon compression, stretching or overload of the muscle [1]. LTrPs can be found in pain-free subjects, and the prevalence of LTrPs in the pectoralis minor (PM) muscle was reported to be nearly 12% in 242 asymptomatic subjects [2]. In addition, the presence of LTrPs in asymptomatic subjects causes a decrease in the efficiency of movement patterns because they produce changes in muscular activity, pseudoweakness of the involved muscle and limitations in the range of motion (ROM) [3–5]. Accordingly, an LTrP in the PM muscle might be implicated in the genesis and maintenance of rounded shoulder posture (RSP) arising from PM muscle tightness. Furthermore, because the PM muscle acts as an accessory muscle in respiration and assists thoracic movement in breathing patterns, it is legitimate to question whether the

tightness of the PM muscle induced by an MTrP could alter respiratory function.

The PM muscle needs to be passively lengthened during the active scapular upward rotation, external rotation, and posterior tipping that occurs with arm elevation [6]. However, an adaptively tightened PM muscle with an LTrP would not demonstrate normal flexibility due to a decreased number of sarcomeres in series and fewer actin-myosin cross-bridges to uncouple [6,7]. Moreover, a tight PM muscle is mostly thought to be related to increased scapular protraction/tilting, forward head posture, RSP and impaired mobility of the upper body quadrant [8]. Recent studies have demonstrated that the PM muscle requires stretching in subjects with RSP [7,8]. However, the most effective method for stretching the PM muscle is still unclear.

The effect of ischemic compression (IC), stretching, myofascial release, strain-counterstrain, skin rolling, and clinical massage for eliminating LTrPs has been investigated [9–11]. It has been suggested that the appropriate MTrP therapy involves lengthening the sarcomeres, * Corresponding author. Istanbul Universitesi-Cerrahpasa, Saglık Bilimleri Fakultesi, Fizyoterapi ve Rehabilitasyon Bolumu, Bakırkoy, Istanbul, Turkey.

E-mail address: fztebrukaya@hotmail.com (E. Kaya Mutlu).

Contents lists available at ScienceDirect

Complementary Therapies in Clinical Practice

journal homepage: http://www.elsevier.com/locate/ctcp

https://doi.org/10.1016/j.ctcp.2019.101080

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as might occur with stretching or IC [12]. During the application of IC, the local MTrP tenderness decreases due to a change in tissue sensitivity; therefore, IC is suggested as an effective therapy for MTrPs [10]. Moreover, studies have shown that MTrP therapy combined with stretching exercises might be more effective for decreasing the pain level and increasing the ROM [9,11]. The addition of manual MTrP therapies to a self-stretching protocol provided superior short-term outcomes compared to a self-stretching program alone in the treatment of subjects with plantar heel pain [11]. Similarly, a program of modified proprio-ceptive neuromuscular facilitation (PNF) stretching combined with cross-fiber friction massage was found to be immediately effective for improving the knee ROM, decreasing stretch perception, increasing the pressure pain threshold (PPT) and reducing subjective pain in subjects with LTrPs [9]. Despite these studies in the current literature, further research is needed to establish the therapeutic effects of different types of stretching exercise combined with IC on LTrPs.

Considering the limited evidence available, it could be hypothesized that IC with PNF stretching might be a more effective approach than other stretching exercises combined with IC for increasing the PM muscle length (PML) in subjects presenting with PM muscle tightness induced by taut bands with MTrPs. However, there is insufficient evi-dence to determine which type of stretching exercise is most effective in combination with IC and its immediate effects on muscle length in subjects with LTrPs. Therefore, this exploratory study aimed to inves-tigate which type of stretching exercise used after IC is more effective in terms of the PML, PPT, pulmonary function, and respiratory muscle strength in subjects with PM muscle tightness and an LTrP in the PM muscle.

2. Materials and methods 2.1. Study design

A single-blind, randomized, controlled pilot trial with a parallel design was carried out in the Physiotherapy and Rehabilitation Department of Istanbul University from April to July 2017.

2.2. Ethical considerations

Ethical approval for this study was obtained from the Human Research Ethics Committee of Bakirkoy Dr. Sadi Konuk Training and Research Hospital (Approval number: 2015-181). The protocol con-formed to the standards for human experiments set by the Declaration of Helsinki.

2.3. Participants

The flyer recruitment method was used to recruit potential partici-pants for this study. Each participant received written and verbal ex-planations of the procedures to be performed, and they were also asked to sign informed consent forms if they agreed to participate. The in-clusion criteria were as follows: 18–35 years of age; PM muscle tight-ness; and at least one LTrP in the PM muscle. PM muscle tightness was defined as a PM muscle index (PMI) less than 7.44 [13]. In a nonclinical population of participants without shoulder dysfunction, LTrPs were diagnosed if the following criteria were met: (1) presence of a palpable taut band in the PM muscle; (2) presence of a tender spot in the taut band; (3) local twitch response elicited by snapping palpation of the taut band; and (4) reproduction of participants’ pain only upon palpation without patient recognition of the symptom as familiar. The MTrP was considered active when the local and referred pain evoked by compression reproduced clinical pain symptoms and the participant recognized the pain as familiar [9,14]. Participants were excluded from the study if they had an ATrP in the PM muscle, any orthopedic problems of the spine or shoulder complex within the last six months or neuro-logical impairment in the upper extremities. Participants who had

received treatment for myofascial pain within the last three months or used anti-inflammatory or pain relief medication in the past 24 h were excluded.

2.4. Study protocol

A total of 40 participants were recruited into this exploratory pilot study because it has been previously indicated that obtaining approxi-mately 10 participants per group could be sufficient to identify mean-ingful differences among groups in pilot studies [15]. Participants were randomly assigned to one of four parallel groups (ratio 1:1:1:1): group 1, IC with modified contract-relax PNF stretching; group 2, IC with static stretching; group 3, IC with myofascial release; or group 4, no inter-vention. “Research Randomizer” is an online randomization web service that was used to allocate the participants (https://www.randomizer. org/). Simple randomization procedures (computerized random numbers) were performed, and sequentially numbered index cards containing the random assignments were prepared by an investigator (a researcher in the faculty) with no clinical involvement in the study to ensure allocation concealment. Then, the physiotherapist (T.B.) per-forming the interventions opened each envelope and allocated the par-ticipants to group 1, group 2, group 3 or group 4 according to the selected index card. A physiotherapist with over ten years of experience in manual therapy performed the trigger point assessment (E.K.M.), while a blinded physiotherapist (R.M.) performed the other assessments and collected the data. Outcome measurements were determined at baseline, immediately after the intervention and 24 h after the inter-vention (Fig. 1).

2.5. Interventions

A single-session intervention of IC was applied in groups 1, 2, and 3. After the single-session intervention of IC was performed, modified contract-relax PNF stretching of the PM muscle was applied in group 1. Static-passive stretching of the PM muscle with an LTrP and myofascial release were applied after the single-session intervention of IC in groups 2 and 3, respectively. No interventions were applied in group 4. For a detailed description of the interventions, see the Appendix.

2.6. Outcome measures

The primary outcome measure for this study was the PMI. The sec-ondary outcomes were the PML, RSP, PPT, pulmonary function, and respiratory muscle strength. The average value of three repeated mea-surements of the PMI, PML, RSP and PPT with a 60-s interval between repetitions was used to minimize the measurement error.

Participants were in a relaxed supine position with their legs bent and their arms by their sides at a neutral position during the assess-ments. The PMI was calculated by dividing the resting muscle length by the participant’s height in centimeters and multiplying by 100. The PMI was developed with normalization because of height and muscle length variability among the participants, and it was used to measure the length of the PM [6,13]. The test-retest reliability for the PMI measurement was 0.94 in a previous study (95% confidence interval [CI] ¼ 0.81–0.98, standard error of measurement [SEM] ¼ 0.32, minimum detectable change with 95% confidence [MDC95] ¼ 0.89, and coefficient

of variation [CV] ¼ 10.60%) [7]. An increased PMI indicates an increased PM length. The resting length of the PM was measured using palpable landmarks, i.e., the inferomedial aspect of the coracoid process and the caudal edge of the fourth rib at the sternum. The linear distance in centimeters between these bony reference points was evaluated using a tape measure. This method of measuring the PML has previously been validated [13]. The distance between the posterior border of the acro-mion and the table, which is a measure of RSP, was measured with a metal scale that was positioned vertically [16].

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digital pressure algometer with a rubber-tipped plunger with a cross- sectional area of 1.0 cm2 mounted on a force transducer (Commander Algometer, JTECH Medical, USA). After the digital pressure algometer was placed on the LTrP, the investigator pressed against the tester in a vertical direction while increasing the force at a constant rate of 1 kg- force per square centimeter. The participants were instructed to express pain by saying "yes" when only slight pain was felt [17]. The digital pressure algometer has been reported as a reliable tool for measuring the PPT and thus the severity of MTrPs [18].

The pulmonary function test was performed as described by the American Thoracic Society [19] and the European Respiratory Society

guidelines [20] using a spirometer. To measure the forced vital capacity (FVC), the forced expiratory volume in the first second (FEV1), the

Tif-feneau index (FEV1/FVC), the peak expiratory flow (PEF) and the

average forced expiratory flow rate over the middle 50% of the FVC (FEF25–75%), a Spirobank II (Medical International Research, S.r.l.,

Rome, Italy) instrument was used. Instructions and demonstrations were given to the participants before the spirometry measurements were taken.

The respiratory muscle strength measurement was performed with the participant seated, wearing a nose clip and a plastic mouthpiece (Micro Medical MicroRPM®, CareFusion Micro Medical, MicroRPM, Fig. 1. CONSORT flow diagram.

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USA). The respiratory muscle strength was assessed by the maximum inspiratory pressure (PIMax) and maximum expiratory pressure (PEMax), as described in the American Thoracic Society and European Respiratory Society statement on respiratory muscle testing [21]. The highest value from five acceptable and reproducible attempts was recorded (i.e., a difference of �10% among values) and is expressed as an absolute value (cmH2O) [21].

2.7. Data analysis

Statistical Package for Social Science (SPSS) version 21.0 for Win-dows software (SPSS, Inc., Chicago, IL, USA) was used for all statistical analyses. Before the statistical analysis, the Kolmogorov–Smirnov test was used to assess the distribution of the data. Demographic data were compared among the four groups by one-way analysis of variance for continuous variables and Chi-squared test for categorical variables. Changes in the mean (95% CI) variable scores within groups were assessed by paired sample t-test. Repeated measures analysis of variance (rANOVA) was conducted with time (baseline, immediately after the intervention, and 24 h after the intervention) as a within-subject vari-able and group (group 1, 2, 3 or 4) as a between-subjects varivari-able to analyze the effect of the interventions on the primary and secondary outcomes. Partial eta-squared was used as an indicator of the effect size (ES), which was determined as small (0.01), medium (0.06) or large (0.14) [22]. The significance level was set at p < 0.05. Once differences among the means were determined, the least significant difference (LSD) post hoc test was used with a Bonferroni correction.

3. Results

Forty participants (mean age, 21.25 � 2.21 years; mean PMI, 6.42 � 0.99) with PM muscle tightness and an LTrP in the PM muscle agreed to participate in the study (Fig. 1). Demographic data and baseline measurements of the outcomes in the four groups are shown in Table 1. There were no significant differences among the groups in any demographic variables or baseline measurements.

The mean difference in the PMI in group 1 and group 3 from baseline to immediately after the intervention was 0.56 � 0.20 and 0.23 � 0.04,

respectively (p ¼ 0.01). Additionally, improvement in the PMI continued from immediately after the intervention to 24 h later in group 1 and group 3 (p ¼ 0.01). However, there was a statistically significant improvement in the PPT only in group 1 immediately after the inter-vention (p ¼ 0.003). The PML was significantly improved in group 1 and group 3 from baseline to immediately after the intervention, with a mean difference of 0.94 � 0.37 and 0.49 � 0.01, respectively (p ¼ 0.01). The overall group-by-time interaction for rANOVA was significant for the PMI (F1,36 ¼3.53, p ¼ 0.02). The mean difference in the PMI in groups 1, 2, 3 and 4 from baseline to 24 h after the intervention was 0.58 � 0.28, 0.22 � 0.27, 0.24 � 0.36 and 0.05 � 0.1, respectively, in favor of group 1 (p ¼ 0.004, p ¼ 0.01, and p ¼ 0.005 for groups 2, 3 and 4, respectively). The between-group ES was large for the significant improvement in the PMI (ES ¼ 0.22) (Table 2).

A significant difference was found in the mean FEV1, PEF, FEV1/FVC,

and PEMax at baseline compared to 24 h after the intervention in group 1 (p ¼ 0.01, p ¼ 0.03, p ¼ 0.03, and p ¼ 0.03, respectively). There was also a statistically significant difference in the mean PIMax and PEMax in group 3 (p ¼ 0.01 and p ¼ 0.03, respectively). However, no statisti-cally significant difference was found between groups in the other outcome measures 24 h after the intervention (p > 0.05) (Tables 2 and 3).

4. Discussion

This pilot study reveals that the addition of modified contract-relax PNF stretching to a single session of IC results in a slightly better im-mediate effect in terms of the PML in participants with PM muscle tightness and an LTrP in the PM muscle. The ES was large for the PML. In addition, the PPT showed a small improvement immediately after the single session of IC combined with modified contract-relax PNF stretching. Changes in the FEV1, PEF, and FEV1/FVC were detected only

in participants who received the single session of IC combined with modified contract-relax PNF stretching. However, the single session of IC combined with myofascial release yielded an improvement in the PIMax and PEMax.

Tightness in muscles involving MTrPs is common due to the abnormal tension and tenderness present in the taut band [23]. Table 1

Demographic data and baseline characteristics in the groups.

Variables Groups p*

Group 1 (n ¼ 10) Group 2 (n ¼ 10) Group 3 (n ¼ 10) Group 4 (n ¼ 10)

Mean � SD Mean � SD Mean � SD Mean � SD

Age (years) 21.60 � 2.71 20.40 � 1.64 22.10 � 2.66 20.90 � 1.85 0.17

Sex (F/M) 9/1 9/1 8/2 8/2 0.26**

BMI (kg/cm2) 22.35 � 3.24 22.36 � 2.55 21.12 � 2.33 21.83 � 2.73 0.23

Pectoralis minor muscle length and rounded shoulder posture

PMI 6.44 � 1.44 6.66 � 1.29 6.36 � 0.56 6.23 � 0.69 0.06

PML (cm) 12.55 � 2.54 12.62 � 2.53 13.86 � 1.17 13.65 � 1.76 0.18

RSP (cm) 7.23 � 0.65 7.74 � 2.05 8.11 � 1.42 8.02 � 1.54 0.56

Pressure pain threshold

PPT (kg/cm2) 4.07 � 2.12 5.21 � 3.25 4.84 � 1.97 4.86 � 2.43 0.28 Spirometry FVC (L) 3.80 � 0.96 3.60 � 0.92 3.72 � 0.68 3.53 � 1.10 0.86 FEV1 (L) 3.41 � 0.68 3.45 � 0.75 3.53 � 0.51 3.27 � 0.83 0.78 PEF (L/s) 6.31 � 1.25 5.79 � 1.57 6.09 � 1.13 6.09 � 1.14 0.77 FEF25–75% (L/s) 4.47 � 0.70 4.22 � 0.96 4.33 � 0.73 4.20 � 1.10 0.80 FEV1/FVC (%) 0.91 � 0.09 0.96 � 0.06 0.95 � 0.07 0.94 � 0.09 0.53

Maximum respiratory pressures

Maximum inspiratory pressure (cmH2O) 67.40 � 17.87 71.10 � 20.96 63.80 � 16.86 66.30 � 26.57 0.57 Maximum expiratory pressure (cmH2O) 75.80 � 20.58 85.30 � 18.26 72.60 � 28.05 81.00 � 32.03 0.57 Group 1: PNF stretching group; group 2: static stretching group; group 3: myofascial release group; group 4: control group.

Abbreviations: BMI, body mass index; cm, centimeter; F, female; FEF25–75%, forced expiratory flow 25–75%; FEV1, forced expiratory volume at the first second; FVC, forced vital capacity; kg, kilogram; L, liter; M, male; n, number; PEF, peak expiratory flow; PML, pectoralis minor muscle length; PMI, pectoralis minor muscle index; RSP, rounded shoulder posture; PPT, pressure pain threshold; s, second; SD, standard deviation.

*One-way analysis of variance (one-way ANOVA); significance level set at <0.05. **Chi-squared test; significance level set at <0.05.

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Additionally, a recent study concluded that the tightness of taut bands with MTrPs was significantly greater than that of the surrounding muscle tissues [24]. It is also well known that LTrPs adversely affect movement patterns due to changes in muscular activity and limitations in the ROM [3,4]. Therefore, manual MTrP therapy and stretching ex-ercises are required to eliminate LTrPs [9,11]. The results of a recent study highlighted the immediate benefits of MTrP therapy combined with modified PNF stretching in young and physically active males with LTrPs [9]. Similarly, the single session of IC combined with modified contract-relax PNF stretching provided a slightly better improvement in the PMI in the present study. These findings support the hypothesis of the present study because the increased PMI indicates lengthening of the PM muscle. The magnitude of improvement in the PMI was not clinically significant, as indicated by the within-group differences in the PMI that were lower than the MDC95 of 0.89 points [7]. However, the findings of

this study suggest that following the application of IC, PNF stretching might be beneficial for decreasing the activity of MTrPs and achieving a greater increase in muscle length.

From a biomechanical point of view, tightness of the PM muscle induced by taut bands with MTrPs might contribute to the presence of RSP, which is one of the more common postural deviations observed clinically [25]. The PM muscle tightness, which is defined as a PMI less than 7.44, might lead to limitations in scapular posterior tipping and external rotation during arm elevation and contribute to shoulder in-juries in healthy subjects; therefore, examining the change in the PMI may assist in treatment planning for PM muscle tightness and RSP [7, 26]. However, no previous studies have examined the PMI in relation to the interventions used in our study, so it is not possible to compare these results directly with those of any other previous studies. On the other

hand, neither the modified contract-relax PNF stretching nor the static passive stretching was found to be effective for correcting RSP in par-ticipants with an LTrP in the PM muscle. Similarly, another study found no acute improvements in scapular upward rotation, external rotation, or posterior tilt after different passive stretching exercises for the PM muscle [27]. Considering these findings, none of the stretching in-terventions applied with a single session of IC may be sufficient to alter RSP immediately.

The single session of IC combined with modified contract-relax PNF stretching yielded an improvement in the PPT immediately after the intervention, whereas this effect was not preserved 24 h after the intervention. On the other hand, there were no significant improve-ments in the PPT after the other two interventions or after no inter-vention. The exact mechanism of the efficacy of PNF stretching in the management of pain perception is still unclear, but it was hypothesized that the gate control theory is a plausible mechanism. It is argued that in PNF stretching, the muscles and tendons are not only stretched but are also contracted at an elongated length, decreasing the nociception, or pain that is sensed and causes inhibition, produced by the Golgi tendon organ. However, further investigation is required to prove or disprove this theory because the PPT is an important outcome measure for assessing the severity of MTrPs [28].

The PIMax is a composite of the pressure generated by the inspira-tory muscles and the elastic recoil pressure of the lungs and chest wall [29]. It was suggested that a decrease in the PIMax would be related to inspiratory muscle fatigue, which interferes negatively with sports performance [30]. A single session of IC combined with myofascial release yielded an improvement in the PIMax, but the other in-terventions did not lead to a significant improvement in the PIMax in the Table 2

Comparison of PML, PMI, RSP and PPT between and within groups. Assessment Baseline

Mean � SD Immediately after intervention Mean � SD

Within-group score change Mean [95% CI]

p* After 24 h

Mean � SD Within-group score change Mean [95% CI]

p* rANOVA

F py Effect

size LSD Group P** Pectoralis minor muscle length and rounded shoulder posture

PMI (%) Group 1 6.44 � 1.44 7.00 � 1.64 0.56 [0.15–0.97] 0.01 7.02 � 1.72 0.58 [-0.19-1.37] 0.01 3.53 0.02 0.22 1–2 1–3 1–4 2–3 2–4 3–4 0.004 0.01 0.005 0.63 0.36 0.66 Group 2 6.66 � 1.29 6.82 � 1.32 0.16 [-0.22-0.55] 0.36 6.88 � 1.56 0.22 [-0.03-0.48] 0.06 Group 3 6.36 � 0.56 6.60 � 0.52 0.23 [0.05–0.41] 0.01 6.60 � 0.92 0.24 [0.05–0.44] 0.01 Group 4 6.23 � 0.69 6.23 � 0.65 0.00 [-0.19-0.19] 0.58 6.28 � 0.78 0.05 [-0.03-0.13] 0.07 PML (cm) Group 1 12.55 � 2.54 13.49 � 2.91 0.94 [0.26–1.62] 0.01 1.21 � 0.08 1.17 [-0.11-2.45] 0.05 2.50 0.07 0.17 – – Group 2 12.62 � 2.53 12.90 � 2.63 0.28 [-0.38-0.95] 0.36 1.17 � 0.06 0.38 [-0.06-0.84] 0.06 Group 3 13.86 � 1.17 14.35 � 1.16 0.49 [0.10–0.88] 0.01 1.15 � 0.04 0.41 [0.09–0.73] 0.63 Group 4 13.65 � 1.76 13.65 � 1.71 0.00 [-0.30-0.30] 0.94 1.14 � 0.03 0.50 [-0.08-1.09] 0.07 RSP (cm) Group 1 7.23 � 0.65 7.39 � 1.13 0.16 [-0.36-0.69] 0.61 0.86 � 0.04 0.05 [-0.41-0.52] 0.81 0.74 0.53 0.05 – – Group 2 7.74 � 2.05 7.35 � 1.58 0.20 [-0.51-0.93] 0.35 0.87 � 0.10 0.12 [-0.79- 0.54] 0.76 Group 3 8.11 � 1.42 8.31 � 1.42 0.20 [0.05–0.35] 0.21 0.90 � 0.06 0.05 [-0.57- 0.46] 0.84 Group 4 8.02 � 1.54 8.11 � 1.59 0.08 [-0.27-0.44] 0.11 0.89 � 0.09 0.02 [-0.38-0.44] 0.90 Pressure pain threshold

PPT (kg/cm2) Group 1 4.07 � 2.12 2.93 � 2.03 1.14 [0.36–1.93] 0.003 0.45 � 0.19 0.06 [-0.81-0.94] 0.41 0.74 0.53 0.05 – – Group 2 5.21 � 3.25 4.57 � 2.19 0.64 [-3.02-1.73] 0.63 0.59 � 0.23 0.77 [-3.51- 1.97] 0.54 Group 3 4.84 � 1.97 4.36 � 2.02 0.48 [-0.26-1.23] 0.11 0.55 � 0.22 0.24 [-0.37-0.86] 0.27 Group 4 4.86 � 2.43 4.81 � 2.19 0.05 [-0.86-0.96] 0.72 0.49 � 0.28 0.09 [-1.37- 1.18] 0.94

Group 1: PNF stretching group; group 2: static stretching group; group 3: myofascial release group; group 4: control group.

Abbreviations: CI, confidence interval; cm, centimeter; kg, kilogram; LSD, least significant difference; PML, pectoralis minor muscle length; PMI, pectoralis minor muscle index; RSP, rounded shoulder posture; PPT, pressure pain threshold; SD, standard deviation.

*Paired sample t-test; significance level set at <0.05.

yRepeated measures analysis of variance (rANOVA); significance level set at <0.05. ** Significance was accepted as p** ¼ 0.05/3 ¼ 0.016 after Bonferroni correction.

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present study. A possible explanation may be that the shortened sarco-meres are lengthened by IC and may then again participate in contrac-tion of the involved muscle [31]. In addicontrac-tion, although its specific causes are not clear, stretch-induced strength loss, which is described as the loss of strength resulting from acute stretching, could explain why the PIMax was not significantly improved in the other groups in which stretching was applied [32]. On the other hand, it is important to emphasize the significant improvement in the PEMax in participants treated with the single session of IC combined with myofascial release or modified contract-relax PNF stretching. The reason for this result is that an in-crease in the activity of the expiratory muscles is accompanied by an increase in the length of the inspiratory muscles through a decrease in muscle activity [33]. It was expected that the PEMax would improve in these participants due to a significant increase in the PMI after the intervention.

This study has some limitations that should be highlighted. First, healthy asymptomatic participants presenting with PM muscle tightness and having an LTrP in the PM muscle were evaluated in our study. Thus, it is essential to conduct a study evaluating the presence of ATrPs. Second, we assessed only the immediate effects of the interventions, so we do not know whether these effects would be preserved over periods longer than 24 h. Third, this study was intended as a pilot study for future research, so the sample size is relatively small; therefore, the findings should be interpreted with caution. Fourth, the sample mainly

comprised females, so the generalizability of the findings may be limited. Finally, we accepted that participants had no health problems according to their declarations.

5. Conclusion

This pilot, randomized, controlled trial, conducted in asymptomatic participants with PM muscle tightness and one or more LTrPs in the PM muscle, demonstrates that IC might be followed by contract-relax PNF stretching exercise to achieve an increase in muscle length. Additionally, a single session of IC combined with contract-relax PNF stretching ex-ercise or myofascial release was better than a single session of IC com-bined with static stretching or no intervention in terms of preserving the PMI and increasing the PML and PEMax. Further studies are required to investigate the long-term effect of IC combined with contract-relax PNF stretching exercise in symptomatic subjects with PM muscle tightness induced by an MTrP.

Ethical approval

Ethical approval for this study was obtained from the Human Research Ethics Committee of Bakirkoy Dr. Sadi Konuk Training and Research Hospital (Approval number: 2015-181).

Table 3

Comparison of respiratory function and respiratory muscle strength between and within groups. Assessment Baseline

Mean � SD After 24 h Mean � SD Within-group score change Mean [95% CI] p* rANOVA F py Effect size (partial eta2) Spirometry FVC (L) Group 1 3.80 � 0.96 3.81 � 0.93 0.00 [-0.05-0.07] 0.63 0.43 0.73 0.03 Group 2 3.60 � 0.92 3.84 � 0.97 0.23 [-0.06-0.52] 0.10 Group 3 3.72 � 0.68 3.70 � 0.38 0.02 [-0.40-0.36] 0.93 Group 4 3.53 � 1.10 3.41 � 1.14 0.12 [-0.53 to 0.13] 0.56 FEV1 (L) Group 1 3.41 � 0.68 3.35 � 0.63 0.06 [-0.11-0.00] 0.01 0.50 0.68 0.04 Group 2 3.45 � 0.75 3.48 � 0.76 0.02 [0.00–0.05] 0.08 Group 3 3.53 � 0.51 3.45 � 0.52 0.07 [-0.17-0.03] 0.14 Group 4 3.27 � 0.83 3.16 � 0.90 0.11 [-0.51-0.29] 0.57 PEF (L/s) Group 1 6.31 � 1.25 6.53 � 1.26 0.22 [0.01–0.43] 0.03 0.18 0.90 0.01 Group 2 5.79 � 1.57 6.27 � 1.36 0.47 [-0.19-1.15] 0.13 Group 3 6.09 � 1.13 6.57 � 0.17 0.48 [-0.16-1.13] 0.47 Group 4 6.09 � 1.14 6.50 � 1.25 0.41 [-0.14-0.97] 0.10 FEF25–75% (L/s) Group 1 4.47 � 0.70 4.38 � 0.85 0.09 [-0.26-0.06] 0.18 0.09 0.96 0.008 Group 2 4.22 � 0.96 4.55 � 0.57 0.33 [-0.19-0.86] 0.14 Group 3 4.33 � 0.73 4.48 � 0.80 0.14 [-0.22-0.51] 0.53 Group 4 4.20 � 1.10 4.44 � 1.43 0.24 [-0.10-0.59] 0.20 FEV1/FVC (%) Group 1 0.91 � 0.09 0.89 � 0.09 0.02 [-0.04-0.00] 0.03 0.58 0.62 0.04 Group 2 0.96 � 0.06 0.91 � 0.09 0.04 [-0.11-0.02] 0.14 Group 3 0.95 � 0.07 0.93 � 0.08 0.02 [-0.09-0.04] 0.52 Group 4 0.94 � 0.09 0.94 � 0.09 0.00 [-0.005-0.006] 0.85 Respiratory muscle strength

Maximum inspiratory pressure (cmH2O)

Group 1 67.40 � 17.87 79.50 � 17.68 10.10 [0.53–19.66] 0.09 0.07 0.97 0.006 Group 2 71.10 � 20.96 77.30 � 18.69 6.20 [-7.93-20.33] 0.34

Group 3 63.80 � 16.86 78.90 � 23.13 15.10 [3.83–26.36] 0.01

Group 4 66.30 � 26.57 79.50 � 25.51 13.20 [-1.40-27.80] 0.44 Maximum expiratory pressure (cmH2O)

Group 1 75.80 � 20.58 87.00 � 22.48 11.20 [1.65–20.74] 0.04 0.66 0.57 0.05 Group 2 85.30 � 18.26 92.70 � 13.19 7.40 [-8.43-23.23] 0.31

Group 3 72.60 � 28.05 83.80 � 28.68 11.20 [0.59–21.80] 0.03

Group 4 81.00 � 32.03 91.40 � 28.26 10.40 [-3.61-24.41] 0.12

Group 1: PNF stretching group; group 2: static stretching group; group 3: myofascial release group; group 4: control group.

Abbreviations: CI, confidence interval; FEF25–75%, forced expiratory flow 25–75%; FEV1, forced expiratory volume at the first second; FVC, forced vital capacity; L, liter; PEF, peak expiratory flow; s, second; SD, standard deviation.

*Paired sample t-test; significance level set at <0.05.

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Declaration of competing interest

With regard to the work, no conflict of interest exists. CRediT authorship contribution statement

Tansu Birinci: Writing - review & editing, Funding acquisition, Formal analysis. Rustem Mustafaoglu: Writing - review & editing, Formal analysis. Ebru Kaya Mutlu: Writing - review & editing, Formal

analysis, Funding acquisition. Arzu Razak Ozdincler: Funding acquisition.

Acknowledgments

This study has been registered on ClinicalTrials.gov with the regis-tration number NCT02699294. The present work was supported by the Scientific Research Projects Coordination Unit of Istanbul University (Project No: TYD-2017-24415).

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.ctcp.2019.101080. Appendix. Detailed description of study interventions

Interventions Details

Ischemic compression Participants were positioned supine on a treatment plinth and were encouraged to relax as much as possible before pressure was applied. Pressure was applied slowly and directly over the marked PM muscle MTrP site until a moderate but tolerable pain value of 7 out of 10 (0 ¼ no pain, 10 ¼ severe pain) was reported. Constant pressure was sustained for 90 s. Then, tissue resistance (barrier) in the PM muscle was controlled [14]. Modified contract-relax PNF

Stretching Participants were in a sitting position with hands clasped behind the head. The PM muscle was passively and slowly stretched until a strong but tolerable stretch discomfort intensity level of 4 out of 10 (0 ¼ no discomfort, 10 ¼ severe discomfort) was reported. The passive stretch was sustained for 10 s followed by 6 s of maximal voluntary isometric contraction of the PM muscle. Then, participants were instructed to relax for a further 4 s. The new position of the stretched PM muscle was maintained for 10 s with a strong but tolerable stretch discomfort intensity level of 4 out of 10. The procedure was repeated four times with 30 s of rest between two successive trials [9].

Static stretching Participants were placed in the lateral recumbent (side lying) position, treatment side up. Then, the physiotherapist slowly brought the participants’ arm in a circular motion overhead pausing at the points of tightness while the physiotherapist’s hand rested on participants’ iliac crest to stabilize the pelvis until a strong but tolerable stretch discomfort intensity level of 4 out of 10 (0 ¼ no discomfort, 10 ¼ severe discomfort) was reported. Passive static stretching of the PM muscle was sustained for 30 s. The procedure was repeated four times with 30 s of rest between two successive trials [34,35].

Myofascial release Participants were positioned supine with the knee bent on a treatment plinth. The physiotherapist’s hands contacted the origin of the PM muscle overlying the anterior surface of the third to fifth ribs. Then, the physiotherapist exerted a gentle caudal force to engage the soft tissues until meeting the comfortable elastic limits of the tissues for 30 s. The procedure was repeated in a gentle and rhythmic fashion four times with 30 s of rest between two successive trials [34].

Abbreviations: MTrP, myofascial trigger point; PNF, proprioceptive neuromuscular facilitation; PM, pectoralis minor. References

[1] D.G. Simons, Review of enigmatic MTrPs as a common cause of enigmatic musculoskeletal pain and dysfunction, J. Electromyogr. Kinesiol. 14 (1) (2004) 95–107.

[2] E.K. Mutlu, T. Birinci, G. Dizdar, A.R. Ozdincler, Latent trigger points: what are the underlying predictors? Arch. Phys. Med. Rehabil. 97 (9) (2016) 1533–1541. [3] J.M. Ibarra, H.-Y. Ge, C. Wang, V.M. Vizcaíno, T. Graven-Nielsen, L. Arendt-

Nielsen, Latent myofascial trigger points are associated with an increased antagonistic muscle activity during agonist muscle contraction, J. Pain 12 (12) (2011) 1282–1288.

[4] H.-Y. Ge, S. Monterde, T. Graven-Nielsen, L. Arendt-Nielsen, Latent myofascial trigger points are associated with an increased intramuscular electromyographic activity during synergistic muscle activation, J. Pain 15 (2) (2014) 181–187. [5] K.R. Lucas, P.A. Rich, B.I. Polus, Muscle activation patterns in the scapular

positioning muscles during loaded scapular plane elevation: the effects of latent myofascial trigger points, Clin. Biomech. 25 (8) (2010) 765–770.

[6] J.D. Borstad, P.M. Ludewig, The effect of long versus short pectoralis minor resting length on scapular kinematics in healthy individuals, J. Orthop. Sport. Phys. Ther. 35 (4) (2005) 227–238.

[7] J.H. Lee, H.S. Cynn, T.L. Yoon, C.H. Ko, W.J. Choi, S.A. Choi, et al., The effect of scapular posterior tilt exercise, pectoralis minor stretching, and shoulder brace on scapular alignment and muscles activity in subjects with round-shoulder posture, J. Electromyogr. Kinesiol. 25 (1) (2015) 107–114.

[8] N. Morais, J. Cruz, The pectoralis minor muscle and shoulder movement-related impairments and pain: rationale, assessment and management, Phys. Ther. Sport 17 (2016) 1–13.

[9] A. Trampas, A. Kitsios, E. Sykaras, S. Symeonidis, L. Lazarou, Clinical massage and modified Proprioceptive Neuromuscular Facilitation stretching in males with latent myofascial trigger points, Phys. Ther. Sport 11 (3) (2010) 91–98.

[10] G. Fryer, L. Hodgson, The effect of manual pressure release on myofascial trigger points in the upper trapezius muscle, J. Bodyw. Mov. Ther. 9 (4) (2005) 248–255. [11] R. Renan-Ordine, F. Alburquerque-Send�In, D.P. Rodrigues De Souza, J.A. Cleland,

C. Fern�andez-de-las-Pe~nas, Effectiveness of myofascial trigger point manual therapy combined with a self-stretching protocol for the management of plantar heel pain: a randomized controlled trial, J. Orthop. Sport. Phys. Ther. 41 (2) (2011) 43–50.

[12] D.G. Simons, Understanding effective treatments of myofascial trigger points, J. Bodyw. Mov. Ther. 6 (2) (2002) 81–88.

[13] J.D. Borstad, Measurement of pectoralis minor muscle length: validation and clinical application, J. Orthop. Sport. Phys. Ther. 38 (4) (2008) 169–174. [14] D.G. Simons, J.G. Travell, L.S. Simons, Travell & Simons’ Myofascial Pain and

Dysfunction: Upper Half of Body, Lippincott Williams & Wilkins, 1999. [15] M.A. Hertzog, Considerations in determining sample size for pilot studies, Res.

Nurs. Health 31 (2) (2008) 180–191.

[16] H.H. Host, Scapular taping in the treatment of anterior shoulder impingement, Phys. Ther. 75 (9) (1995) 803–812.

[17] J.L. Reeves, B. Jaeger, S.B. Graff-Radford, Reliability of the pressure algometer as a measure of myofascial trigger point sensitivity, Pain 24 (3) (1986) 313–321. [18] G. Park, C.W. Kim, S.B. Park, M.J. Kim, S.H. Jang, Reliability and usefulness of the

pressure pain threshold measurement in patients with myofascial pain, ann, Rehabil. Med. 35 (3) (2011) 412–417.

[19] Standardization of Spirometry, 1994 Update. American thoracic society, Am. J. Respir. Crit. Care Med. 152 (3) (1995) 1107–1136.

[20] M.R. Miller, J. Hankinson, V. Brusasco, F. Burgos, R. Casaburi, A. Coates, et al., Standardisation of spirometry, Eur. Respir. J. 26 (2) (2005) 319–338. [21] ATS/ERS Statement on respiratory muscle testing, Am. J. Respir. Crit. Care Med.

166 (4) (2002) 518–624.

[22] H.C. de Vet, C.B. Terwee, L.M. Bouter, Current challenges in clinimetrics, J. Clin. Epidemiol. 56 (12) (2003) 1137–1141.

[23] K.R. Lucas, B.I. Polus, P.A. Rich, Latent myofascial trigger points: their effects on muscle activation and movement efficiency, J. Bodyw. Mov. Ther. 8 (3) (2004) 160–166.

[24] Q. Chen, S. Bensamoun, J.R. Basford, J.M. Thompson, K.N. An, Identification and quantification of myofascial taut bands with magnetic resonance elastography, Arch. Phys. Med. Rehabil. 88 (12) (2007) 1658–1661.

[25] S. Raine, L.T. Twomey, Head and shoulder posture variations in 160 asymptomatic women and men, Arch. Phys. Med. Rehabil. 78 (11) (1997) 1215–1223. [26] J.S. Lewis, C. Wright, A. Green, Subacromial impingement syndrome: the effect of

changing posture on shoulder range of movement, J. Orthop. Sport. Phys. Ther. 35 (2) (2005) 72–87.

[27] J.G. Williams, K.G. Laudner, T. McLoda, The acute effects of two passive stretch maneuvers on pectoralis minor length and scapular kinematics among collegiate swimmers, Int. J. Sports. Phys. Ther. 8 (1) (2013) 25–33.

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[28] K.B. Hindle, T.J. Whitcomb, W.O. Briggs, J. Hong, Proprioceptive neuromuscular facilitation (PNF): its mechanisms and effects on range of motion and muscular function, J. Hum. Kinet. 31 (2012) 105–113.

[29] P. Caruso, A.L.P. de Albuquerque, P.V. Santana, L.Z. Cardenas, J.G. Ferreira, E. Prina, et al., Diagnostic methods to assess inspiratory and expiratory muscle strength, J. Bras. Pneumol. 41 (2) (2015) 110–123.

[30] M. Karsten, G.S. Ribeiro, M.S. Esquivel, D.L. Matte, Maximizing the effectiveness of inspiratory muscle training in sports performance: a current challenge, Phys. Ther. Sport 36 (2019) 68–69.

[31] B. Cagnie, V. Dewitte, I. Coppieters, J. Van Oosterwijck, A. Cools, L. Danneels, Effect of ischemic compression on trigger points in the neck and shoulder muscles in office workers: a cohort study, J. Manip. Physiol. Ther. 36 (8) (2013) 482–489.

[32] M.P. McHugh, C.H. Cosgrave, To stretch or not to stretch: the role of stretching in injury prevention and performance, Scand. J. Med. Sci. Sport. 20 (2) (2010) 169–181.

[33] A.V. Gorkovenko, S. Sawczyn, N.V. Bulgakova, J. Jasczur-Nowicki, V. S. Mishchenko, A.I. Kostyukov, Muscle agonist–antagonist interactions in an experimental joint model, Exp. Brain Res. 222 (4) (2012) 399–414. [34] C.K. Wong, D. Coleman, V. diPersia, J. Song, D. Wright, The effects of manual

treatment on rounded-shoulder posture, and associated muscle strength, J. Bodyw. Mov. Ther. 14 (4) (2010) 326–333.

[35] G.E. Lawson, L.Y. Hung, G.D. Ko, M.A. Laframboise, A case of pseudo–angina pectoris from a pectoralis minor trigger point caused by cross-country skiing, J. Chiropr. Med. 10 (3) (2011) 173–178.

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