Table 2 Study objectives, participants, and conditions for performing the inter-recti distance (IRD) measurement using ultrasonographic imaging (USI) in 49 study protocols
Study objectives | Participants | Body position during assessment at rest* | Assessment during specific muscle activity/task | Breathing | |
|---|---|---|---|---|---|
Abuín-Porras 2019 (Spain) [42] | To compare abdominal muscle thickness and IRD between female rugby players and non-athletes | 32 nulliparas: 16 rugby players, mean age: 24.7 ± 4.9 yr, BMI: 23.4 (21.9–24.7); 16 non-athletes, mean age: 27.9 ± 6.1 yr, BMI: 22.8 (20.5–25.7) | Supine | Not applicable | At the end of expiration |
Arranz-Martín 2022 (Spain/Canada) [74] | To determine the acute effect of an abdominal hypopressive exercise (AHE) on IRD, linea alba distortion, and abdominal muscle thickness among primiparous women and to compare this effect with that of other abdominal exercises | 46 primiparas at 3mo after singleton vaginal delivery, mean age: 35 ± 4 yr; median BMI: 22.7 (interquartile range: 21.1–25.8) | Hook lying | - AHE: trunk axially extended, wrists, ankles dorsiflexed, shoulders medially rotated; after one breathing cycle, in apnea, ribs expanded laterally, abdominal wall moved inward and cranially - ADIM: after one breathing cycle, navel drawn in toward the spine - Semi curl-up: after breathing cycle, head and shoulders off the table, arms at sides, inferior scapular angles in contact with the table - ADIM + semi curl-up | Pattern/phase related to specific exercise |
Balasch-Bernat 2021 (Spain) [56] | To evaluate the differences in IRD and abdominopelvic function between nulliparous, primiparous and multiparous women | 75 women: 25 primiparas and 25 multiparas at 6mo after vaginal delivery, and 25 nulliparas; mean age: 34.2 ± 2.6, 35.0 ± 4.0, 33.2 ± 4.6 yr, respectively; BMI: 23.4 ± 4.2, 22.3 ± 3.0, 22.3 ± 2.9, respectively | Supine, slight knee and hip flexion, a pillow under the knees, arms along the body | - ADIM: after inhaling and exhaling, navel drawn in toward the spine - Curl-up: head and shoulders lifted, lower scapular angles off the examination table | Not specified |
Barbosa 2013 (Brazil) [60] | To investigate the accuracy of IRD measurement using a caliper compared with USI | 106 paras 72 h after delivery (62.2% cesarean, 37.8% vaginal), parity: 2.2 ± 1.4, mean age: 27.1 ± 6 yr, BMI: 25.9 ± 6.8 | Supine, lower limbs flexed, and feet on a bed | - Trunk flexed, scapulae off the support, and arms along the body | Not specified |
Beamish 2019 (Canada) [8] | To investigate the impact of the measurement site and task on IRD, linea alba stiffness, and distortion, and to assess the relationships between the linea alba parameters | 20 women (9 nulliparas and 11 paras ≥ 1 yr after vaginal delivery: 1 primipara, 10 multiparas) with and without DRA, mean age: 31 ± 8 yr, BMI: 25.3 ± 3.9 | Supine, thin pillow under the head, and arms along the body | - Head lift: head gently lifted off the pillow - semi curl-up: head and shoulders lifted and inferior angles (not the spines) of the scapulae in contact with the examination table | At the end of expiration (breathing paused for image capture) |
Belo 2020 (Brazil) [61] | To determine the reliability and accuracy of IRD measurement using a caliper compared with USI | 54 pregnant women at 28–41wk gestation, mean age: 24.6 ± 5.6 yr, BMI: 29.3 ± 5.1 | Supine, hips and knees flexed, feet on a bed, and arms by the side | - Trunk flexed and lower borders of scapulae off the bed | During expiration |
Benjamin 2020 (Australia) [67] | To determine the criterion validity of the use of a caliper, tape measure, and finger width to evaluate IRD compared with USI | 50 paras ≥ 6wk postpartum (26 primiparas, 24 multiparas, delivery: 21 vaginal, 19 cesarean, and 10 vaginal with instrumentation, age: 32.8 ± 4.8 yr, BMI not reported | Supine, knees flexed to 90°, arms by the side | - Modified abdominal sit-up: arms crossed over the chest, head raised, and inferior angles of the scapulae off the surface | At the end of expiration |
Castellanos-López 2022 (Spain) [57] | To compare anteroposterior diameter of the levator ani hiatus, abdominal muscle thickness, and IRD between women with and without dyspareunia | 32 non-pregnant, non-postpartum women: 16 with dyspareunia (mean age: 25.4 ± 3.4 yr, BMI: 21.7 ± 2.9), 16 without dyspareunia (mean age: 26.7 ± 4 yr, BMI: 22.8 ± 1.7) | Supine, pillow under the head, hips and knees flexed | - Abdominal contraction: arms crossed over the chest, upper trunk raised, spines of the scapulae off the examination table | Breathing phase considered irrelevant |
Chiarello 2013 (USA) [62] | To assess the concurrent validity of the use of digital calipers and USI for the measurement of IRD | 56 subjects (11 men, mean age: 37.5 ± 9.8 yr, BMI: 30 ± 3.9; 22 nulliparas, mean age: 28.5 ± 6 yr, BMI: 23.4 ± 4; 23 paras, mean age: 39.6 ± 9.8 yr, BMI: 22.6 ± 1.8 | Hook lying, pillow under the head, arms by the side | - Partial curl-up: arms crossed over the chest, head and spine of the scapulae off the examination table | Not specified |
Chiarello 2016 (USA) [9] | To determine whether IRD decreases with active abdominal contraction in men and nulliparous and parous women | 56 subjects (11 men, mean age: 37 ± 10 yr, BMI: 30 ± 3.9; 22 nulliparas, mean age: 27.9 ± 5.9 yr, BMI: 23.4 ± 4; 23 paras, mean age: 39.2 ± 9.7 yr, BMI: 22.6 ± 1.8 | Same as Chiarello (2013) [62] | Same as Chiarello (2013) [62] | Not specified |
Coldron 2008 (UK) [16] | To compare the RA size and shape and IRD between day 1 and month 2, 6, and 12 postpartum, and between paras and nulliparas | 72 primiparas, 43 multiparas at day 1 and month 2, 6, and 12 postpartum, mean age: 32 yr (19–46 yr, and 69 nulliparas, mean age: 27 yr (18–45 yr), BMI not reported | Crook lying, knees flexed over two pillows | Not applicable | Not specified |
Corvino 2019 (Italy) [10] | To categorize the anatomical variations of DRA | 92 women: 10 without DRA and 82 with DRA (5 nulliparas; 77 paras, parity: 1–4, last delivery: 48 vaginal, 29 cesarean), mean age: 35 yr (30–51 yr), BMI not reported | Supine, pillow under head, knees slightly flexed, and arms along the trunk | Not applicable | In a neutral moment immediately after expiration |
Crommert 2021 (Sweden) [68] | To investigate how physical and psychological factors are linked to disability attributed to symptoms from an increased IRD in paras | 139 paras at 1–8 yr since last delivery with IRD ≥ 2 finger widths (38% with at least one cesarean section), mean age: 37 ± 4.9 yr, BMI: 23.9 ± 3.5 | Supine, knees flexed to 90° | Not applicable | At the end of expiration |
Da Cuña-Carrera 2021 (Spain) [11] | To assess the IRD at rest and during abdominal crunch, abdominal crunch with TrA preactivation, and abdominal hypopressive exercise (AHE) | 98 healthy subjects: (64 non-pregnant nulliparas and 32 men), mean age: 22.4 ± 3.6 yr, BMI: 22.8 ± 2.7 | Supine, knees flexed to 90° , feet supported, and arms along the body | - Abdominal crunch: arms crossed over the chest, head and scapulae off the surface - Abdominal crunch + TrA preactivation - AHE: arms above the shoulders; after deep exhalation, breath-holding with rib expansion | At the end of expiration |
Depledge 2021 (New Zealand) [64] | To determine the (immediate) effect of four abdominal exercises, Tubigrip and taping in reducing DRA at 3 wk postpartum | 29 paras with DRA after vaginal delivery (mean age: 32 ± 4.6 yr, days postpartum: 21 ± 4, body height: 166 ± 5.9 cm, body mass: 65 ± 7.9 kg) | Crook lying, hips, and knees flexed to 90° | - ADIM + PFM activation - Curl-up: head, scapulae off the examination table, hands along thighs directed toward the knees - Sahrmann early level single leg raise with ADIM; supine, one leg flexed (90° hip flexion) - modified McGill side-lying plank: hip off the examination table to align trunk and thigh - ADIM, curl-up + Tubigrip, taping | Immediately after relaxed expiration (in a stable position held for 3–4 s) |
Eisenberg 2021 (Israel) [27] | To investigate the clinical and morphological relationships between DRA and pelvic floor trauma in primiparas | 36 primiparas (vaginal delivery), with birth-related pelvic floor trauma: 18 with DRA, mean age: 27.8 ± 4.7 yr, BMI: 23.7 ± 4.1, and 18 without DRA, mean age: 26.8 ± 4.2 yr, BMI: 23.7 ± 3.5 | Supine, knees and pelvis flexed to 90° | - Abdominal curl: head and shoulders lifted, spines of the scapulae off the examination table, hands reaching the knees | At the end of expiration |
Fan 2020 (Italy and Canada) [12] | To investigate differences between abdominal muscles and fasciae in women, depending on delivery mode and in comparison with nulliparas | 36 women: 23 primiparas ≥ 2 yr after delivery (13 cesarean, mean age: 41.7 ± 6.1 yr, BMI: 23.7 ± 2.5 and 10 vaginal, mean age: 47 ± 15.2 yr, BMI: 21.5 ± 2.8 and 13 nulliparas, mean age: 27.1 ± 14.2 yr, BMI: 21.6 ± 1.4 | Supine | Not applicable | At the end of expiration |
Fernandes da Mota 2015 (Portugal and Norway) [15] | To assess the prevalence and risk factors of DRA in pregnant/postpartum women and their relationships with lumbopelvic pain | 84 primiparas (at 35wk gestation, 6–8, 12–14, and 24–26wk postpartum; delivery: 52 vaginal, 32 cesarean); at 6mo postpartum: 33 with DRA, mean age: 31.6 ± 2.2 yr, BMI: 22.3 ± 3.7, and 51 without DRA, mean age: 32.5 ± 2.9 yr, BMI: 22.5 ± 3.2 | Same as Mota (2012) [49] | Not applicable | At the end of expiration |
Gillard 2018 (UK) [63] | To assess the effect of posture and the measurement site on IRD, and to assess the reliability of the measurement in paras | 41 women (12 primiparas and 29 multiparas) between 2mo and 28 yr (mean, 9.8 ± 8.9 yr) after vaginal delivery, mean age: 43 ± 9 yr, BMI: 25.2 ± 4 | Crook lying, pillow under the head, legs hip-width apart, knees flexed to 90°, feet facing forward, and mid-pelvic alignment | Postural muscle tone: - Sitting position: feet flat on the floor, arms resting on the thighs, and mid-pelvic alignment - standing position: legs hip-width apart, arms along the body, and mid-pelvic alignment | At the end of expiration |
Gluppe 2020 (Norway) [13] | To investigate the immediate effects of abdominal and PFM exercises on IRD in paras with DRA | 38 paras > 6wk postpartum with DRA [4 primiparas and 34 multiparas (parity: 2–4), after vaginal and cesarean deliveries], mean age: 36.2 ± 5.2 yr, BMI: 23.2 ± 3.6 | Supine, hips and knees flexed, and feet on a table | Head lift, curl-up, PFM contraction, PFM contraction + curl-up, maximal ADIM, PFM contraction + maximal ADIM, pelvic tilt, and twisted curl-up (to the left and the right) | At the end of expiration |
He 2021 (China) [65] | To determine the utility of shear wave elastography in assessing abdominal muscles in women with and without DRA | 36 postpartum women with DRA (32 cesarean, 4 vaginal delivery), mean age: 28.6 ± 3.7 yr, pre-pregnancy BMI: 20.2 ± 2.0, parity, days postpartum not specified; 24 nulliparas, mean age: 26.8 ± 4.7 yr, BMI: 20.6 ± 2.1) | Supine, arms across the chest | Not applicable | Not specified |
Hills 2018a (Canada) [53] | To determine the influence of the transducer tilt in cranial and caudal directions on IRD measurement | 15 paras (5 primiparas, 10 multiparas, delivery: 9 vaginal, 6 cesarean; 7/15 with DRA), mean age: 39.4 ± 8 yr, BMI: 29.2 | Supine and legs extended | - Head lift: head lifted with the neck in line with the spine, and the scapula in contact with the examination table | Not specified |
Hills 2018b (Canada) [17] | To compare the trunk muscle function between women with and without DRA at 1 yr postpartum | 40 primiparas at 1 yr postpartum (delivery: 31 vaginal, 9 cesarean): 18 with DRA, mean age: 31.9 ± 3.6 yr, BMI: 25.1 ± 5.6, and 22 without DRA, mean age: 31.2 ± 4.5 yr, BMI: 24.1 ± 3.9 | Supine, knees and hips flexed, and arms by the side | Not applicable | At the end of tidal expiration |
Iwan 2014 (New Zealand) [47] | To assess the reliability of IRD measurement using high- and low-resolution USI, and to compare measurements by novice and experienced sonographers | 30 subjects: 14 men, mean age: 24.2 ± 8.3 yr, BMI: 24.4 ± 2.5, and 16 women (13 nulliparas, mean age: 21.8 ± 1.9 yr, BMI: 23.9 ± 2.8, and 3 postpartum, mean age: 36 ± 6.7 yr, BMI: 21.5 ± 2.4 | Supine, pillow under head, knees flexed to 90°, feet on a table, and arms along the body | - Partial curl-up: arms crossed over the chest and head and scapulae off the examination table | At the end of expiration |
Keshwani 2015a (Canada) [48] | To investigate the intrarater between-session reliability of IRD measurement | 20 primiparas, multiparas with DRA at 3mo to 17 yr (mean: 3 yr) since last delivery (9 cesarean), mean age: 36 ± 6 yr, BMI: 26.1 ± 7 | Supine and pillow under the head | - Head lift: with the neck in line with the spine, head gently lifted off the pillow (head touching the pillow but not supported) | Not specified |
Keshwani 2015b (Canada) [54] | To investigate the criterion-related validity and reliability of IRD measurement using extended field of view (standoff pad and panoramic mode) in paras | 21 non-pregnant primiparas and multiparas with IRD ≤ 3 finger widths (to visualize the entire IRD with conventional USI), mean age: 40 ± 6 yr, BMI: 22.8 ± 1.9 | Supine, pillow under the head, and arms by the side | Not applicable | During expiration |
Keshwani 2016 (Canada) [55] | To investigate the interrater reliability of IRD measured at rest and during head lift in paras | 17 primiparas and multiparas at 6mo to 25 yr (mean: 7 yr) since last delivery; mean age: 38 ± 8 yr, BMI: 26.4 ± 7.3 | Supine, pillow under the head, neck in line with the spine | Same as Keshwani (2015a) [48] | Not specified |
Keshwani 2018 (Canada) [20] | To investigate the relationship between IRD and symptom severity in the early postpartum period | 32 postpartum primiparas with DRA detected at 3–4wk after vaginal delivery; mean age: 32 ± 2 yr, BMI: 25 ± 3.7 | Supine, pillow under the head, and arms by the side | Not applicable | Not specified |
Keshwani 2019 (Canada) [33] | To explore the feasibility of abdominal binding and trunk exercises for the management of DRA | 29 primiparas with DRA (first assessment at 3–4wk postpartum); mean age: 31.5 yr, BMI: 24.7 | Supine | Not applicable | Not specified |
Kim 2022 (Korea) [69] | To investigate the efficacy of 6-wk core stabilization exercise program conducted in person and through real-time video conferencing on IRD and abdominal muscle thickness in women with DRA at 6-12mo postpartum | 37 DRA women 6-12mo postpartum [online group (9 vaginal, 10 cesarean delivery), mean age: 31.7 ± 3.9 yr, BMI: 22 ± 1.9; direct contact group (6 vaginal, 12 cesarean delivery), mean age: 32.7 ± 2.5 yr, BMI: 22.8 ± 1.9]; parity not specified | Supine | Not applicable | During normal respiration |
Lee 2016 (Australia and Canada) [34] | To investigate IRD and linea alba distortion during curl-ups performed naturally and with TrA preactivation | 26 DRA subjects: 25 paras and 1 nullipara; mean age: 34 ± 4 yr, BMI: 20.6, and 17 non-DRA subjects: 11 nulliparas, mean age: 25 ± 2 yr, BMI: 20.4, and 6 males, mean age: 28 ± 3 yr, BMI: 23.5 | Supine, pillow under the head, hips and knees flexed, feet on a table, and arms by the side | - Curl-up: head and neck lifted, top of the scapulae off the bed, and arms along the body - Curl-up + preactivated TrA by gentle PFM contraction | Not specified |
Li 2022 (China) [66] | To investigate the effects of progressive yoga exercise program on IRD among women in the early postpartum period | 116 primiparas, vaginal delivery [63 yoga exercisers (mean age: 31, BMI: 21.4 ± 2); 53 controls (mean age: 30, BMI: 21.7 ± 2.1)], IRD assessed at postpartum wk 6 and 12 | Supine, relaxed abdominal muscles | Not applicable | Not specified |
Liaw 2011 (Taiwan) [18] | To investigate IRD natural recovery and abdominal muscle strength in women postpartum and to examine the relationship between IRD and abdominal muscle function | 30 paras (17 primiparas, 13 multiparas) at 7wk (4–8 wk) and 6mo (6–8mo) after vaginal delivery, mean age: 32.1 ± 3 yr, BMI: 21.5 ± 2.8; 20 nulliparas, mean age: 31.9 ± 4.1 yr, BMI: 20.7 ± 2.7 | Supine and 2 pillows under the knees | Not applicable | At the end of expiration |
Mota 2012 (Portugal and Norway) [49] | To evaluate the test–retest and intrarater reliability of IRD measurement (during rest and a specific task), and to investigate IRD in postpartum women | 24 women: 12 postpartum (< 6mo), mean age: 31.2 yr (26–36 yr), BMI: 24 (20.8–28.5); 12 with parity 0–2, mean age: 29.9 yr (16–55 yr), BMI: 21.5 (18.9–24.6) | Supine, knees flexed to 90°, feet on a table, and arms along the body | - Abdominal crunch: head and shoulders raised upward, scapulae off the examination table - ADIM: after inhalation, abdominal muscles drawn in toward the spine with exhalation | At the end of expiration |
Mota 2013 (Portugal and Norway) [71] | To evaluate the reliability of IRD examination with abdominal palpation and compare palpation with USI | 20 paras, mean parity: 0.7 (0–2), age: 29.3 yr (16–49 yr), BMI: 23 (18.9–28.5); 12/20 in the postpartum period | Same as Mota (2012) [49] | - Abdominal crunch: head and shoulders raised upward, scapulae off the examination table | At the end of expiration |
Mota 2015 (Portugal and Norway) [35] | To evaluate the immediate effect of drawing-in and abdominal crunch exercises on IRD in pregnancy and postpartum | 84 primiparas (at 35–41wk gestation and 6–8, 12–14, and 24–26wk postpartum; delivery: 52 vaginal and 32 cesarean), mean age: 32 yr (25–37 yr), BMI not reported | Same as Mota (2012) [49] | - Abdominal crunch: head and shoulders raised upward (while exhaling), scapulae off the table - ADIM: after inhalation and exhalation, and the navel drawn in toward the spine | Immediately at the End of expiration |
Mota 2018 (Portugal and Norway) [72] | To establish “normal” IRD values in primiparas during pregnancy and postpartum | 84 primiparas (at 35–41wk gestation and 6–8, 12–14, 24–26 wk postpartum; delivery: 52 vaginal and 32: cesarean), mean age: 32.1 ± 2.7 yr; BMI not reported | Same as Mota (2012) [49] | Not applicable | At the end of expiration |
Morales 2018a (Spain) [43] | To compare the perimuscular connective tissue and IRD between elite and amateur basketball players | 22 men (11 elite and 11 amateur basketball players), mean age: 21 ± 6 yr, BMI: 22.6 ± 2.6 | Supine | Not applicable | At the end of expiration |
Morales 2018b (Spain) [58] | To assess abdominal muscle thickness and IRD during the drawing-in maneuver with a proprioceptive Stabilizer | 41 healthy subjects, mean age: 31.9 ± 4.5 yr, BMI: 22.9 ± 2.7 | Supine | - ADIM (with the use of Stabilizer) | At the end of expiration |
Nanikawa 2021 (Japan) [50] | To assess the reliability of abdominal wall perimuscular connective tissue measurement | 38 healthy men, mean age: 21.6 ± 0.5 yr, BMI not reported | Supine and arms relaxed | Not applicable | At the end of expiration |
Pascoal 2014 (Portugal) [36] | To determine the effect of abdominal muscle isometric contraction on IRD in postpartum women | 10 primiparas (1–5mo postpartum, delivery: 9 vaginal and 1 cesarean), mean age: 30 ± 4 yr, BMI: 24.1 ± 7.0, and 10 nulliparas, mean age: 28 ± 2 yr, BMI: 21.7 ± 5.3 | Supine, knees flexed to 90° (crook lying), feet on a table, and arms along the trunk | - Abdominal crunch: head and shoulders raised upward, scapulae off the examination table, and fingertips touching knees | At the end of expiration |
Romero-Morales 2018 (Spain) [59] | To compare RA thickness and IRD between patients with Achilles tendinopathy (AT) who underwent an eccentric exercise (EE) program with vibration and EE program with cryotherapy | 61 subjects with AT randomly divided; grade I: 4 men, 26 women receiving EE + vibration, mean age: 41.1 ± 8.2 yr, BMI: 25.2 ± 2.5, gr II: 5 men, 26 women receiving EE + cryotherapy, mean age: 42.1 ± 9.2 yr, BMI: 24.8 ± 2.4 | Supine | - Calf muscle maximal isometric contraction | At the end of expiration |
Romero-Morales 2019 (Spain) [44] | To compare and quantify IRD and abdominal muscle measures between subjects with and without Achilles tendinopathy (AT) | 143 subjects (71 with AT, mean age: 45.1 ± 12.7 yr, BMI: 24.8 ± 2.1, and 72 without AT, mean age: 37.6 ± 11.9 yr, BMI: 23.9 ± 3.7 | Supine | Not applicable | Not specified |
Romero-Morales 2020 (Spain) [45] | To compare abdominal muscles thickness and IRD in women with and without primary dysmenorrhea (PD) | 39 women (19 with PD, mean age: 20 ± 4 yr, BMI: 21.6 ± 3.3 and 20 without PD, mean age: 22.5 ± 7 yr, BMI: 21.5 ± 3.7 | Supine, hips and knees flexed, and arms along the body | Not applicable | At the end of expiration |
Sancho 2015 (Portugal and Norway) [73] | To compare IRD at rest between women who delivered vaginally and by C-section; to describe the effect of different abdominal exercises on IRD | 38 postpartum primiparas after singleton gestation (23 after vaginal delivery, mean age: 31.2 ± 3.6 yr, BMI 22.9 ± 2.7, and 15 after cesarean section, mean age: 32.3 ± 4.4 yr, BMI: 22.8 ± 2.8) | Supine, knees flexed to 90°, feet on a table, and arms along the body | - Abdominal crunch: head, shoulders raised upward, scapulae off the table, fingertips touching the knees - ADIM: after inhalation, abdominal muscles drawn in toward the spine with exhalation - ADIM + abdominal crunch | Immediately at the end of expiration |
Starzec-Proserpio 2022 (Poland) [70] | To evaluate the differences between early postpartum women with and without pelvic girdle pain (PGP) regarding pubic symphysis separation, IRD, and pain catastrophizing | 105 women 24-72 h after vaginal delivery, 35 with PGP (mean age: 32.9 ± 4.5 yr, pre-pregnancy BMI: 24.5 ± 4.5) and 70 without PGP (mean age: 33.0 ± 4.2 yr, pre-pregnancy BMI: 22.5 ± 3.2), each group parity: 1.8 ± 0.9) | Supine | - Curl-up: head and upper torso raised, scapulae off the table | Not specified |
Theodorsen 2019 (Norway) [37] | To assess the effect of the PFM and TrA muscles contraction on IRD in postpartum women with DRA | 38 women 0–26wk postpartum (parity: 1–3) with DRA (delivery: 31 vaginal, 4 vaginal/forceps, 3 cesarean; 4 multiple births), mean age: 34.6 ± 4.0 yr, BMI: 24.2 ± 3.3 | Supine, pillow under head, knees hip-width apart, flexed to 90°, feet on a table, and arms along the body | - PFM contraction - ADIM - PFM contraction + ADIM | At the end of expiration |
Theodorsen 2022** (Norway) [75] | To investigate the effect of a specific exercise program during pregnancy on DRA after the 12-wk intervention and postpartum | Of 100 gravidas with DRA at gestational wk 24 (primigravidas and multigravidas), 50 will be assigned to exercise group and 50 to non-intervention group; IRD to be measured at 24 and 37wk gestation, and at 6wk, 6 and 12mo postpartum | Supine, head on a pillow, arms alongside the body, knees hip-width apart, bent to 90°, feet on a table | Not applicable | Immediately at the end of expiration |
Whittaker 2013 (UK and Canada) [46] | To compare the resting thickness of the abdominal muscles, perimuscular connective tissue, and IRD in persons with and without lumbopelvic pain (LPP) | 50 male and female subjects: 25 with LPP, mean age: 46.6 ± 8 yr, BMI: 24.0 ± 3.5, and 25 without LPP, mean age: 36.3 ± 9.4 yr, BMI: 23.5 ± 2.5 | Supine | Not applicable | At the end of expiration |