Thoracic Expansion vs DNS Exercises in Forward Head Posture

Official title

A Randomized Controlled Trial Comparing Thoracic Expansion Exercises and Dynamic Neuromuscular Stabilization on Respiratory Function and Bilateral Trapezius Muscle Activity in Individuals With Forward Head Posture

Overview

This randomized controlled trial aims to compare the effects of thoracic expansion exercises and Dynamic Neuromuscular Stabilization (DNS) on respiratory function and bilateral trapezius muscle activity in individuals with forward head posture (FHP). A total of 32 participants aged 18-40 years with a craniovertebral angle (CVA) of less than 53° will be randomly assigned to either the DNS group or the thoracic expansion exercise group. Primary outcomes include respiratory function (FEV1, FVC, FEV1/FVC), trapezius muscle activation measured with EMG biofeedback, and craniovertebral angle. Secondary outcomes include thoracic mobility and health-related quality of life assessed using the St. George's Respiratory Questionnaire. Both interventions will be applied for 6 weeks. The study aims to determine which approach provides greater improvement in posture-related respiratory dysfunction and muscle activation.

Detailed description

Forward head posture (FHP) is a common postural deviation characterized by reduced craniovertebral angle (CVA), altered cervicothoracic alignment, and compensatory activation of accessory respiratory muscles. Individuals with FHP frequently demonstrate limited thoracic mobility, decreased respiratory efficiency, and increased demand on superficial neck musculature. These biomechanical alterations may negatively influence pulmonary function parameters such as FEV1 and FVC, as well as contribute to elevated electromyographic (EMG) activity in the upper trapezius muscles.

Various therapeutic approaches have been developed to address posture-related respiratory dysfunction. Thoracic expansion breathing exercises aim to enhance chest wall mobility and improve lung expansion across upper, middle, and lower thoracic regions. Dynamic Neuromuscular Stabilization (DNS), based on developmental kinesiology principles, seeks to optimize diaphragmatic function, intra-abdominal pressure regulation, and coordinated activation of deep stabilizing musculature. Although both methods have theoretical benefits for improving respiratory mechanics and postural alignment, comparative evidence regarding their differential effects in individuals with FHP remains limited.

This randomized controlled trial will investigate the immediate and short-term effects of thoracic expansion breathing exercises versus DNS-based stabilization exercises on respiratory function, cervicothoracic posture, and muscle activation patterns. Thirty-two adults aged 18-40 years with a CVA of less than 53° will be enrolled and randomly assigned using an opaque envelope method to one of two intervention groups: the Thoracic Expansion Exercise Group or the Dynamic Neuromuscular Stabilization Group. Each intervention protocol will be implemented over a 6-week period, consisting of twice-weekly supervised sessions complemented by twice-daily home exercise routines.

Outcome assessments will be conducted at baseline and at the end of the 6-week intervention period. These assessments will include: CVA measured by standardized lateral photography and ImageJ analysis; bilateral upper trapezius muscle activity assessed using surface EMG biofeedback; pulmonary function tests (FEV1, FVC, FEV1/FVC) conducted with spirometry; thoracic expansion measured at three levels using a tape-measure chest mobility test; and health-related quality of life evaluated with the St. George's Respiratory Questionnaire (SGRQ). The study protocol was approved by the Istanbul Medipol University Non-Interventional Clinical Research Ethics Committee.

This trial is designed to provide a comparative analysis of two commonly used physiotherapy interventions for FHP, with a focus on their effects on posture-related respiratory mechanics, thoracic mobility, and neuromuscular activation. All findings will be reported separately in the Results section. The present description outlines the scientific rationale, study design, and intervention procedures without duplicating eligibility criteria or outcome measure definitions.

Interventions

• Behavioral Dynamic Neuromuscular Stabilization Exercises
  Participants in the DNS group will perform Dynamic Neuromuscular Stabilization exercises based on developmental kinesiology principles. The program consists of three standardized DNS patterns: Supine 90°/90° Position (4.5-month developmental stage): The participant lies supine with hips and knees flexed to 90°, emphasizing diaphragmatic breathing, rib cage expansion, and neutral spine alignment. Prone on Elbows (4.5-month stage): The participant supports the upper body on elbows while maintain
• Behavioral Thoracic Expansion Exercise
  Participants in the thoracic expansion group will perform a structured breathing exercise program focused on increasing upper, middle, and lower thoracic mobility. The program includes: Upper Lobe Expansion Exercise: Participant places hands over upper thoracic region and performs deep inhalation to expand upper lung fields, followed by slow exhalation. Middle Lobe Expansion Exercise: Hands placed laterally at mid-thoracic level to facilitate expansion of the middle lobes during inhalation. L

Primary outcome measures

• Craniovertebral Angle (CVA) [Time frame: Baseline and Week 6]

Secondary outcome measures (5)

• Trapezius Muscle Activity (Surface EMG Biofeedback, µV) [Time frame: Baseline and Week 6]
• FEV1 (Forced Expiratory Volume in 1 Second) [Time frame: Baseline and Week 6]
• FVC (Forced Vital Capacity) [Time frame: Baseline and Week 6]
• Thoracic Expansion (Chest Mobility, cm) [Time frame: Baseline and Week 6]
• St. George's Respiratory Questionnaire (SGRQ) Total Score [Time frame: Baseline and Week 6]

Eligibility criteria

Inclusion criteria

• Adults aged 18 to 40 years.
• Craniovertebral angle (CVA < 53°) indicating forward head posture.
• Able to perform exercise-based interventions.
• Voluntarily agrees to participate and signs the informed consent form.
• No neurological, orthopedic, systemic, or cardiopulmonary conditions that would limit participation.

Exclusion criteria

• Contraindications to exercise (e.g., acute musculoskeletal injury, uncontrolled cardiovascular disease).
• Chronic upper respiratory tract disease that may affect spirometry results. Presence of a cardiac pacemaker.
• Neurological disorders, systemic diseases, or mental impairments that could interfere with exercise cooperation.
• History of orthopedic or musculoskeletal surgery affecting mobility or posture.
• Currently participating in respiratory exercises, spinal stabilization training, or structured exercise programs.
• Engagement in professional sports or intensive physical training that may affect baseline neuromuscular measurements.
• Failure to comply with the exercise program (e.g., missing 3 consecutive days of prescribed exercises).

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Treatment

Study locations

Turkey (Türkiye) · 1 center

• Mudanya University — Bursa

Identifiers

NCT: NCT07238660 · MU-FHP-DNS-TE-2025-01

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗