The Effect Of Stretching Exercise on Pectoralis Minor Myofascial Latent Trigger Points
Condition: Myofascial Trigger Point Pain
MeSH terms: Myofascial Pain Syndromes
Study type: Interventional

Summary: 
      This randomised-controlled trial investigates whether a single intervention of manual
      pressure release combined with stretching exercise has an effect on muscle length, pain
      perception threshold, and respiratory function in subjects with latent myofascial trigger
      point in the pectoralis minor muscle or not. First quarter of the participants will receive a
      single intervention of manual pressure release combined with contract-relax PNF stretching
      exercise of pectoralis minor muscle, second quarter of the participants will receive a single
      intervention of manual pressure release combined with Z stretching exercise of pectoralis
      minor muscle while, only a single intervention of manual pressure release will be applied to
      third quarter of the participants and final quarter of them will not receive any
      intervention.
    

Detailed description: 
      Myofascial trigger points are hyperirritable points located within a taut band of skeletal
      muscle or fascia, which cause referred pain, local tenderness and autonomic changes when
      compressed. They are classified as either active myofascial trigger points (ATrPs) or latent
      myofascial trigger points (LTrPs). ATrPs can be inactivated by different treatment
      strategies; however, they never fully disappear but rather convert to the latent form.
      Therefore, the diagnosis and treatment of LTrPs is important. Invasive and noninvasive
      techniques are available for management of LTrPs. Invasive techniques include trigger point
      injections and dry needling whereas noninvasive techniques include manual therapy techniques
      and electrotherapy modalities. Manual therapy techniques for the treatment of myofascial
      trigger points include joint manipulation, strain/counterstrain, ischemic compression and
      pressure, massage therapy, myofascial release therapy, muscle energy techniques, point
      pressure release and transverse friction massage. Additionally, recent studies showed that
      the myofascial trigger point therapy combined with stretching exercise may be an effective
      for decreasing the pain level. However, there is insufficient evidence to determine what type
      stretching exercise is most effective and its immediate effects on muscle length in people
      with LTrPs. Therefore, the aim of this randomised-controlled trial is to investigate the
      effect on muscle length, pain perception threshold, and respiratory function after a single
      intervention of manual pressure release combined with stretching exercise on LTrPs in the
      pectoralis minor muscle.

      The sample size and power calculations is performed with the sample size calculator (InStat).
      The calculations is based on a standard deviation of 0.5 points, the minimal clinically
      important difference (MCID) for Pectoralis Minor Index of 0.89 points, an alpha level of
      0.05, a β level of 5%, and a desired power of 95%. These parameters generate a sample size of
      at least 9 participants for each group. Total of 40 subjects will be recruited into the study
      in order to allow for a loss to follow-up.

      Potential participants will be invited through the posting of flyers at Istanbul University,
      Turkey. Flyer recruitment method will be used in this trial because it is the most effective,
      yielding the highest number of enrolments. All participants will be completed an informed
      consent form that described the purpose and procedures of testing. prior to participating in
      the study. Forty participants fitting the inclusion criteria will be randomly assigned to one
      of four parallel groups (ratio 1:1:1:1). For allocation of the participants,
      "Randomization.com" which is an online, randomisation web service will be used
      (http://www.randomization.com/). Simple randomisation procedures (computerized random
      numbers) will be done and sequentially numbered index cards with the random assignment will
      be prepared by an investigator with no clinical involvement in the study. The index cards
      will be folded and placed in sealed opaque envelopes. Then, the blind investigator will open
      each envelope and allocate the participants to group according to selected index card. The
      interventions will be performed by the same physiotherapist at a university research clinic,
      and assessments and data collection will be made by another therapist. Whereas
      interventionist will be aware of the allocated arm, patients and outcome assessor will be
      kept blind to allocation.

      The data will be evaluated using the Statistical Package for the Social Sciences 21.0 program
      for Windows and by analyzing descriptive statistics (frequency, mean and standard deviation).
      Kolmogorov-Smirnov Test will be used to assess the distribution of data. The one-way analysis
      of variance (ANOVA) for repeated measures with the Bonferroni post hoc test will used to
      determine whether differences in the mean scores of outcome measure among three time points
      (baseline, immediate after and 24 hours later) between study groups. In this study, p values
      less than 0.05 will be regarded as statistically significant.
    

Intervention name(s): Manual pressure release; Contract-relax PNF stretch; Z-stretch
Intervention type(s): Other; Other; Other
Intervention description(s): Subjects will be positioned supine on a treatment plinth and will be encouraged to relax as much as possible before pressure is applied. A slow pressure to myofascial latent trigger point will be applied directly over the marked pectoralis minor muscle myofascial latent trigger point site until a moderate but tolerable pain value of 7 out of 10 (0= no pain, 10= severe pain) is reported. Constant pressure will be sustained for 90 seconds if the subjects report that the pain is decreased to a value of 3, the pressure will be increased to restore perceived pain to the value of 7. Then, tissue resistance (barrier) in pectoralis minor muscle will be controlled.; Subjects will be in a sitting position with hands being clasped behind the head. The pectoralis minor muscle will be passively and slowly stretched until a strong but tolerable stretch discomfort intensity level of 4 out of 10 (0= no pain, 10= severe pain) is reported. Passive stretch will be sustained for 10 seconds followed by 6 seconds of maximal voluntary isometric contraction of the pectoralis minor muscle. Then, subjects will be instructed to relax for further 4 seconds. Subjects will maintain newly active stretched position of pectoralis minor muscle for 10 seconds with a strong but tolerable stretch discomfort intensity level of 4 out of 10. The procedure will be repeated four times with 30 seconds of rest between two successive trials.; Subjects will be positioned supine with knee bent on a treatment plinth, and the legs will be rotated to the opposite direction of the arm to be stretched placing a stabilizing distal tension on the ribs. Then, the subjects will be slowly brought the arm in a circular motion overhead pausing at the points of tightness, maintaining close contact to the treatment table until a strong but tolerable stretch discomfort intensity level of 4 out of 10 (0= no pain, 10= severe pain) is reported. Self-stretch of pectoralis minor muscle, including myofascial latent trigger points will be sustained for 30 seconds. The procedure will be repeated four times with 30 seconds of rest between two successive trials.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Pain Threshold; Pectoralis Minor; Proprioceptive Neuromuscular Facilitation (PNF) Stretching; Physiotherapy; Rehabilitation