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.
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
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
33
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
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
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.
Lahore University of biological and applied sciences
Lahore, Punjab Province, Pakistan
Pakistan Society for Rehabilitation of Differently Abled
Lahore, Punjab Province, Pakistan
Inter-rectus Distance (IRD)
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.
Time frame: Baseline: Before starting the intervention Post-intervention: At the end of 6 weeks of the exercise program
Core stability
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.
Time frame: Baseline (pre-intervention) and 6 weeks (post-intervention)
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