Effects of Transverse Abdominis Activation and Rectus Abdominis Strengthening on Inter-rectus Distance and Core Stability (TrA RA IRD DRA)

November 19, 2025 updated by: Lahore University of Biological and Applied Sciences

Effects of Transverse Abdominis Activation and Rectus Abdominis Strengthening on Inter-rectus Distance and Core Stability Among Patients With Diastasis Rectus Abdominis

This randomized controlled trial aims to compare the effects of Transverse Abdominis (TrA) activation, Rectus Abdominis (RA) strengthening, and their combined approach on inter-rectus distance (IRD) and core stability in postpartum women diagnosed with diastasis rectus abdominis (DRA). Thirty-three participants will be randomly allocated into three groups and will complete a six-week exercise program at the Pakistan Society for the Rehabilitation of the Disabled (PSRD) Hospital, Lahore. The study will use real-time ultrasound and pressure biofeedback assessment to evaluate changes in IRD and core stability. It is hypothesized that TrA activation and the combined intervention will produce greater improvements compared to RA strengthening alone.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Background and Rationale:

Diastasis Rectus Abdominis (DRA) is a prevalent postpartum musculoskeletal condition characterized by the separation of the rectus abdominis muscles along the linea alba, resulting in impaired trunk stability, abdominal weakness, and postural dysfunction. Despite its high prevalence, DRA remains underdiagnosed and undertreated, particularly in developing countries where structured rehabilitation protocols are lacking. Physiotherapy-based interventions focusing on abdominal muscle retraining and core stability have been shown to improve outcomes; however, the relative effectiveness of Transverse Abdominis (TrA) activation, Rectus Abdominis (RA) strengthening, and their combined approach remains uncertain.

Objectives:

This randomized controlled trial aims to compare the effects of TrA activation, RA strengthening, and their combination on inter-rectus distance (IRD) and core stability among postpartum women with DRA.

Methods:

This three-arm, parallel-group randomized controlled trial will be conducted at the Pakistan Society for the Rehabilitation of the Disabled (PSRD) Hospital, Lahore, Pakistan. A total of 33 postpartum women aged 20-40 years, diagnosed with DRA (6 months to 2 years postpartum), will be recruited using non-probability convenience sampling. Participants will be randomly assigned into three groups (n = 11 per group):

Group A (TAA): Transverse Abdominis Activation exercises

Group B (RAS): Rectus Abdominis Strengthening exercises

Group C (TAA + RAS): Combined TrA activation and RA strengthening protocol

Each participant will undergo a 6-week intervention program, including three supervised sessions per week for 3 weeks, followed by a 3-week home exercise program. Each session will last 30-45 minutes and will be supervised by a licensed physical therapist at PSRD.

Outcome Measures:

Primary Outcome: Change in Inter-Rectus Distance (IRD), measured via real-time ultrasound imaging (7.5 MHz linear probe) at three anatomical sites (4.5 cm above, at, and 4.5 cm below the umbilicus), pre- and post-intervention.

Secondary Outcome: Core stability, assessed using a Pressure Biofeedback Unit (PBU) during the abdominal drawing-in maneuver (ADIM) in crook-lying position. Participants will aim to reduce pressure by 6-10 mmHg from a 40 mmHg baseline and sustain the contraction for 10 seconds; the mean of three trials will be recorded.

Randomization and Blinding:

Participants will be randomized using Randomized Allocation Software (Version 1.0) in a 1:1:1 ratio. Due to the exercise-based nature of the interventions, blinding of participants and therapists is not feasible; however, the outcome assessor will remain blinded to group assignments, ensuring a single-blind design.

Data Analysis:

Statistical analysis will be performed using SPSS version 26. Data will first be tested for normality using the Shapiro-Wilk test. A two-way mixed ANOVA will be applied to assess both within-subject effects (time: pre vs. post) and between-subject effects (group: TAA, RAS, TAA+RAS), as well as the interaction effect (time × group) on IRD and core stability outcomes. Post-hoc pairwise comparisons with Bonferroni correction will identify specific between-group differences. Statistical significance will be set at p < 0.05 with a 95% confidence interval.

Expected Clinical Significance:

It is hypothesized that TrA activation exercises will lead to a greater reduction in IRD and improvement in core stability compared to RA strengthening alone. The combined exercise group (TAA + RAS) is expected to demonstrate the most comprehensive benefits due to synergistic activation of both deep and superficial abdominal muscles. The study outcomes are anticipated to provide evidence-based guidance for physiotherapists in postpartum rehabilitation, contributing to the development of standardized, non-invasive exercise protocols for DRA management and improved quality of life in postpartum women.

Study Type

Interventional

Enrollment (Estimated)

33

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Pakistan
    • Punjab Province
      • Lahore, Punjab Province, Pakistan
        • Lahore University of Biological and Applied Sciences
        • Contact:
      • Lahore, Punjab Province, Pakistan
        • Pakistan Society for Rehabilitation of Differently Abled
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

. Postpartum women diagnosed with DRA

  • Multigravida
  • Delivered a singleton pregnancy via vaginal breech or instrumental delivery

Exclusion Criteria:

. Pregnancy

  • Abdominal and pelvic hernias or severe musculoskeletal conditions
  • Patients with abdominal and pelvic surgery
  • Patients with disc herniation

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Group A (Transverse abdominis activation)
Other: Transverse Abdominis activation exercises
Group A (TAA) will perform abdominal drawing-in maneuvers (ADIM) in crook lying, side lying, and quadruped positions. They will be instructed to gently draw the belly button inward toward the spine without moving the pelvis or rib cage, emphasizing breathing coordination and pelvic floor co-activation. In the supervised phase, participants will perform 3 sets of 10 repetitions, with each contraction held for 10-20 seconds, and a rest interval of 3 minutes between sets
Experimental: Group B (Rectus abdominis strengthening)
Other: Rectus Abdominis Strengthening exercises
Group B (RAS) will perform exercises in supine lying with knees bent, including partial curl-ups, reverse crunches, pelvic tilts, and leg raises with abdominal bracing. The command will be tighten your abdominals as if bracing for a punch, and lift without straining your neck. Each supervised session will include 3 sets of 10-15 repetitions per exercise, progressing in difficulty using added resistance if tolerated, with a 3-minute rest interval between sets
Experimental: Group C (Transverse abdominis activation +rectus abdominis strengthening)
Other: combined protocol of both transverse abdominis activation and rectus abdominis strengthening.
Group C (TAA+RAS) will perform a hybrid protocol integrating both TrA activation and RA strengthening exercises. Each session will begin with ADIM in crook lying, side lying, and quadruped positions, followed by RA exercises including curl-ups, pelvic tilts, and leg raises. The command will be to activate your deep core with breathing, then strengthen your outer abdominals through controlled movements. Each supervised session will consist of 3 sets of 10 repetitions for TrA exercises (10-20 seconds hold) and 3 sets of 10-15 repetitions for RA exercises, with a rest period of 3 minutes between all sets.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Inter-rectus Distance (IRD)
Time Frame: Baseline: Before starting the intervention Post-intervention: At the end of 6 weeks of the exercise program
The Inter-rectus Distance (IRD) is the measurement of the separation between the two rectus abdominis muscles along the linea alba. It is assessed using ultrasound imaging while the participant is in a supine position with knees bent.. A high-frequency (7.5 MHz) linear probe will be placed on the abdomen while the patient lies on their back. Images will be taken at three points above, at, and below the belly button.
Baseline: Before starting the intervention Post-intervention: At the end of 6 weeks of the exercise program

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Core stability
Time Frame: Baseline (pre-intervention) and 6 weeks (post-intervention)
core stability was assessed using the pressure biofeedback unit (PBU), a reliable and non-invasive tool designed to evaluate the activation and control of deep abdominal muscles, particularly TrA. The PBU consists of a pressure cuff connected to an analog pressure gauge and provides visual feedback on pressure changes in response to subtle lumbo pelvic movements (57). For assessment, participants were positioned in a crook lying position, and the cuff was positioned under the lumbar spine (L4-L5 region). The device was inflated to a baseline pressure of 40 mmHg, and participants will be instructed to perform the abdominal drawing-in maneuver, aiming to reduce the pressure by 6-10 mmHg without moving the pelvis or spine. They were asked to maintain this contraction for 10 seconds, and the procedure will be repeated three times, with the average score recorded for analysis.
Baseline (pre-intervention) and 6 weeks (post-intervention)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Lahore University of Biological and Applied Sciences

Investigators

  • Study Chair: Muhammad tariq Shafi, BSPT,tDPT, Lahore University of Biological and Applied Sciences

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

November 25, 2025

Primary Completion (Estimated)

May 25, 2026

Study Completion (Estimated)

May 30, 2026

Study Registration Dates

First Submitted

November 19, 2025

First Submitted That Met QC Criteria

November 19, 2025

First Posted (Actual)

November 28, 2025

Study Record Updates

Last Update Posted (Actual)

November 28, 2025

Last Update Submitted That Met QC Criteria

November 19, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • UBAS/ERB/FoRS/25/025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data (IPD) will be shared, including demographic characteristics (age, parity, BMI), baseline and post-intervention ultrasound measurements of inter-rectus distance (IRD), abdominal muscle strength scores, and functional outcome or patient-reported measures related to abdominal function. Data will also include group allocation (Transverse Abdominis Activation or Rectus Abdominis Strengthening) for analysis comparison. All shared data will be stripped of any personal identifiers to ensure participant confidentiality. The shared dataset will be available in a coded format for secondary analysis and research transparency purposes only.

IPD Sharing Time Frame

The de-identified individual participant data (IPD) and supporting documents (study protocol, statistical analysis plan, and informed consent form) will be made available after completion of data analysis and publication of the main study results, approximately 6 months after study completion. The data will remain accessible for a period of 3 years following the publication date. Requests for data access must be submitted to the principal investigator and will be reviewed to ensure appropriate use consistent with ethical and confidentiality standards. No personally identifiable information will be shared at any stage.

IPD Sharing Access Criteria

De-identified individual participant data (IPD) and supporting information (study protocol, analysis plan, and informed consent form) will be available to qualified researchers, academicians, and postgraduate students conducting studies related to abdominal rehabilitation, physiotherapy, or maternal health. Access will be provided upon reasonable written request to the principal investigator, accompanied by a brief research proposal and data use agreement ensuring confidentiality. Approved users will receive the data in an electronic, password-protected format via institutional email. The data will be shared solely for academic and non-commercial research purposes, with strict adherence to ethical and privacy standards.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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