Diastasis recti abdominis (DRA) often persists beyond the early postpartum. Although exercise is first-line treatment, existing protocols are limited by early initiation, brief durations, and insufficient loading, focusing on curl-ups and isolated transversus abdominis (TrA) and pelvic floor muscle (PFM) contractions [1]. Despite evidence supporting diaphragm’s role in lumbopelvic stability, the impact of targeted loading using Inspiratory Muscle Training (IMT) on functional postpartum rehabilitation remains underexplored [2]. This original study evaluated a 12-week rehabilitation protocol combining progressive trunk stabilization exercise (PTSE) and IMT for late-stage DRA, hypothesizing that IMT+PTSE would be more effective than supervised PTSE alone or unsupervised basic exercises (Control) in reducing inter-recti distance (IRD) and improving trunk endurance (TE).

This three-arm, parallel-group RCT included women aged 18-50, 6 months to 5 years postpartum, with IRD ≥2.8cm, and ultrasound (US)-confirmed TrA/PFM control. Exclusion criteria included pregnancy, early postpartum (<6 months), serious comorbidities, major surgery (excluding cesarean), and BMI>30 kg/m². Following informed consent, participants were randomized (computer-generated blocks, concealed allocation) into (1) PTSE: supervised blended progressive trunk stabilization (blended in-person and telerehabilitation), focusing on PFM/TrA, lumbopelvic control, and functional loading, (2) IMT+PTSE: PTSE plus IMT (3x/weekly, 50-80% Maximal Inspiratory Pressure) via pressure threshold device, and (3) Control: home-based, unsupervised basic inner core contractions.  All groups trained 3x/weekly for 12 weeks. Adherence was monitored with exercise diaries. Outcomes, assessed by blinded examiners included US-measured IRD at 2cm above the umbilicus (primary) at baseline and 12 weeks, and TE, assessed via curl-ups, front/side planks and McGill’s TΕ test at baseline, 4, 8 and 12 weeks [3]. Repeated Measures ANOVA was employed with Bonferroni-corrected pairwise comparisons applied where appropriate (p<0.05).

Out of seventy-five participants initially randomized, sixty-four completed the study (15% attrition; aged 38.9±4.5, 30.98±20.12 months postpartum; PTSE=21, IMT+PTSE=21, Control=22), exceeding the a-priori power analysis target of 48 (G*Power 3.1.9.7; f = 0.30, a=0.05, power=0.95). All groups demonstrated significant within-group IRD reductions at 12 weeks (p<0.001; Mean differences PTSE=-0.50 cm, IMT+PTSE=-0.52 cm, and CG=-0.40 cm; 95% CI range: 2.55-3.73), without any between-group differences (p>0.05). Significant Time effects were observed for TE (p< 0.001, η2p = 0.19-0.35). Statistically significant Time x Group interactions favored IMT+PTSE and PTSE groups for planks (p<0.05, η2p = 0.07-0.08) and McGill’s test (p=0.002, η2p = 0.12). Post-hoc analysis demonstrated early functional gains (front/left side plank, McGill’s test) of IMT+PTSE compared to Control at weeks 4 and 8 (p= 0.001-0.04), without however significant differences by week 12 and, confirmed superior front plank endurance for PTSE vs. Control at 12 weeks (p=0.03).  No significant TE differences were found between PTSE and IMT+PTSE.

Inspiratory muscle training did not prove superior to PTSE or Control groups in IRD reductions and TE at 12 weeks. However, significant mid-intervention TE improvements against Control might support a potential role of IMT in accelerating functional adaptations. Yet, more regular and intensive IMT protocols may have been required to elucidate its full impact. While mechanical loading might provide modest IRD reductions in the late postpartum period, regardless of exercise complexity, supervised PTSE might provide a superior neuromuscular stimulus for functional recovery and TE; PTSE protocol yielded greater improvements in plank and McGill’s tests, tasks that challenge the lateral abdominal wall and global stability, which is often affected by DRA.

More research is needed regarding IMT inclusion in DRA rehabilitation to determine its long-term effects. For late-stage postpartum, supervised PTSE+IMT, PTSE, and unsupervised basic exercises provide modest IRD reductions. While traditional basic contractions remain an accessible option, structured and progressive trunk stabilization may optimize functional rehabilitation in the later postpartum period.

Skoura A, Billis E, Papanikolaou DT, et al. Diastasis Recti Abdominis Rehabilitation in the Postpartum Period: A Scoping Review of Current Clinical Practice. Int Urogynecol J. 2024;35(3):491-520.
Hodges PW, Gandevia SC. Changes in intra-abdominal pressure during postural and respiratory activation of the human diaphragm. J Appl Physiol (1985). 2000;89(3):967-976.
] Skoura A, Antoniou M, Thanatsis N, et al. Feasibility and Preliminary Efficacy of a Telerehabilitation Intervention for Diastasis Recti Abdominis-A Pilot Study. Healthcare (Basel). 2025;13(17):2224.