Immediate Effects of Strain Counterstrain Versus Fascial Distortion Model on Upper Trapezius Latent Trigger Points

Immediate Effects of Strain Counterstrain Versus Fascial Distortion Model on Pain and Function in Individuals With Latent Myofascial Trigger Points of the Upper Trapezius: A Pilot Study

This pilot study aimed to compare the immediate effects of two manual therapy techniques, strain counterstrain (SCS) and the fascial distortion model (FDM), on pain-related outcomes and neuromuscular function in individuals with latent myofascial trigger points of the upper trapezius muscle. Twenty healthy adults with identified latent trigger points were randomly assigned to receive a single session of either SCS or FDM. Cervical range of motion, proprioception, pressure pain threshold, and cervical muscle strength were assessed before and immediately after the intervention. This study was conducted to obtain preliminary data regarding the short-term effects of two manual therapy approaches with contrasting stimulation characteristics.

Study Overview

• Status: Completed
• Conditions: Latent Myofascial Trigger Points; Upper Trapezius Muscle
• Intervention / Treatment: Other: Strain Counterstrain; Other: Fascial Distortion Model

Detailed Description

Musculoskeletal pain of the cervical region is a prevalent health problem, and the upper trapezius muscle is frequently involved due to postural overload and mechanical stress. These factors are commonly associated with the development of latent myofascial trigger points, which may restrict range of motion and impair neuromuscular function even in the absence of spontaneous pain.

Various manual therapy techniques have been used to manage myofascial trigger points. Strain counterstrain (SCS) is an indirect, low-intensity technique that aims to reduce nociceptive input and muscle spindle activity by positioning the body in a pain-free posture. In contrast, the fascial distortion model (FDM) is a direct manual therapy approach that applies relatively high-intensity pressure to specific fascial distortions identified through patient body language and palpation.

This study was designed as a pilot, parallel-group, pre-post comparative trial to explore the immediate effects of SCS and FDM on pain-related and neuromuscular outcomes in individuals with latent myofascial trigger points of the upper trapezius. Twenty healthy adults were randomly assigned to receive a single session of either SCS or FDM. Cervical range of motion, joint position error, pressure pain threshold, and cervical muscle strength were assessed before and immediately after the intervention. The findings of this study are intended to provide preliminary evidence to inform future large-scale clinical trials comparing manual therapy techniques with differing stimulation characteristics.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• South Korea
  • Gyeongsangnam-do
    • Changwon, Gyeongsangnam-do, South Korea, 51767
      • Kyungnam University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy adults aged 18 to 39 years.
• Presence of latent myofascial trigger points in the upper trapezius muscle.
• No history of neurological or orthopedic disorders within the past six months.
• Willingness to participate and provision of written informed consent.

Exclusion Criteria:

• Current or previous complaints of neck or shoulder pain.
• Ongoing treatment for musculoskeletal conditions.
• History of physical therapy or chiropractic treatment within the past six months.
• History of surgery or trauma involving the head or upper trunk.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Strain Counterstrain Group; Participants received a single session of strain counterstrain manual therapy applied to latent myofascial trigger points of the upper trapezius muscle.	Other: Strain Counterstrain; Strain counterstrain is an indirect manual therapy technique in which the body is passively positioned in a pain-free posture to reduce nociceptive input and muscle tension. In this study, a single session of strain counterstrain was applied to latent myofascial trigger points of the upper trapezius muscle.
Experimental: Fascial Distortion Model Group; Participants received a single session of fascial distortion model manual therapy applied to latent myofascial trigger points of the upper trapezius muscle.	Other: Fascial Distortion Model; The fascial distortion model is a direct manual therapy approach that applies localized, high-intensity pressure to specific fascial distortions identified through patient body language and palpation. In this study, a single session of fascial distortion model intervention was applied to latent myofascial trigger points of the upper trapezius muscle.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cervical Range of Motion	Active cervical range of motion was measured using a Cervical Range of Motion (CROM) device in flexion, extension, lateral flexion, and rotation.	Before and immediately after the intervention
Pressure Pain Threshold	Pressure pain threshold at the latent myofascial trigger point of the upper trapezius muscle was measured using a digital algometer.	Before and immediately after the intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cervical Proprioception	Cervical proprioception was assessed using joint position error during cervical lateral flexion measured with a CROM device.	Before and immediately after the intervention
Cervical Muscle Strength	Isometric cervical muscle strength was measured using a digital muscle tester during flexion, extension, lateral flexion, and rotation.	Before and immediately after the intervention

Collaborators and Investigators

• Sponsor: Kyungnam University
• Investigators: Principal Investigator: JiYoung Kim, PT, PhD, Kyungnam University

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2025
• Primary Completion (Actual): October 31, 2025
• Study Completion (Actual): October 31, 2025

Study Registration Dates

• First Submitted: January 18, 2026
• First Submitted That Met QC Criteria: January 18, 2026
• First Posted (Actual): January 26, 2026

Study Record Updates

• Last Update Posted (Actual): January 26, 2026
• Last Update Submitted That Met QC Criteria: January 18, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Manual Therapy; Upper Trapezius; Myofascial Trigger Point; Fascial Distortion Model; Strain Counterstrain
• Other Study ID Numbers: JYK-2025-02

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No