Introduction

The abdominal muscles are crucial for regulating abdominal pressure and maintenance of good posture, breathing patterns, and structural waist stability. As the uterus continuously enlarges during pregnancy, the abdominal white line and the deep fascia of the abdomen are constantly stretched, which poses a great challenge to the abdominal muscles. The most common clinical problem during the postpartum period is Rectus abdominis diastasis (RAD), which can injure the abdominal muscles, tendons, and fascia, leading to respiratory disorders, lumbosacral or pelvic pain, and physical abnormalities2. In the early postpartum period, the incidence of RAD in China was approximately 35–60%1. Majority of women in the third trimester of pregnancy will exhibit varying degrees of rectus abdominis separation. Rectus abdominis muscle separation can lead to postpartum abdominal wall insufficiency (PPAWI). PPAWI is a pathological condition affecting women after pregnancy characterized by anterior abdominal wall laxity with RAD, induced by abdominal distension during gestation3,4 .RAD has gradually attracted the attention of obstetricians and gynecologists, abdominal wall plastic surgeons, rehabilitation therapists, and women in the postpartum period. In China, biomimetic stimulation, exercise training, acupuncture, and soft tissue therapy techniques, among others, are common non-surgical treatments for RAD. However, these treatments have limitations, such as the poor efficacy of abdominal exercises in the treatment of rectus abdominis muscle separation5,6. Although acupuncture is effective, its success is highly dependent on the skill of the practitioner7. Kinesio Taping (KT) therapy technique, developed by Japanese chiropractor Kenzo Kase, involves applying a special elastic patch to lift the skin or subcutaneous tissue in various directions., This technique increases subcutaneous space, promotes local blood and lymphatic circulation, and induces mechanical and neurophysiological effects on the skin, which contribute to muscle recovery, motor function restoration, and enhanced proprioception. KT has gained popularity due to its non-invasive nature8,9. The direction and elastic force of KT tape are the key to the treatment of various diseases, and there are certain clinical requirements for the physiotherapist’s technique. In RAD therapy, KT bands are primarily used to provide continuous tension to hold the separated muscles in place. KT also has structural remodeling effects on skin and fascia relaxation in abdominal wall dysfunction10,11. Although the use of KT in RAD treatment has been clinically reported, the sample size remains limited, and published reports in China are nonexistent. This study aimed to retrospectively analyse the use of KT in the treatment of postpartum RAD since 2017 and evaluate the clinical efficacy of KT in the treatment of RAD and the relationship between KT treatment and corresponding abdominal changes.

Participants, ethics and methods

Study methods

The medical records of women diagnosed with RAD at the outpatient clinic from October 2017 to March 2023 were reviewed. A total of 138 women who received KT for postpartum rectus abdominis separation and met the inclusion criteria were included in the study. The inclusion criteria were as follows: women aged1 20–46 years old;2 RAD ≥ 2 cm in at least one of three sites; and3 ≥ 3 KT treatments. The exclusion criteria were as follows:1 allergies related to KT treatment;2 women with diabetes with skin complications;3 pregnancy complicated by hypertension, eclampsia, and other complications;4 gave birth ≥ 3 times; and5 history of abdominal surgery other than Cesarean section. Patient demographic data, KT treatment data, and evaluation data before and after treatment were collected for statistical analysis.

Ethics statements

The Ethics Committee of West China Second Hospital of Sichuan University approved this study. An exemption from informed consent for the clinical data required for the study was requested and granted by the Ethics Committee. It was also confirmed that all procedures were performed in accordance with the relevant guidelines and regulations of the Ethics Committee. Due to the retrospective nature of the study, the Ethics Committee of West China Second Hospital of Sichuan University waived the requirement to obtain informed consent.

Interventions

The Green Clinic, measuring 5 cm x 500 cm, was used for the KT treatment. KT was used to cross the patch with the outer edge of the rectus abdominis as the anchor point for the lower abdomen, mid-abdomen, and upper abdomen (Fig. 1). A 30–50% tension was used to apply abdominal pressure. During taping, the therapist stands on the left or right side of the patient alternately to ensure a balanced bilateral ligation tension. Taping was performed by two physiotherapists, each with more than 5 years of experience in kinesiology taping and standardized training in application techniques. Treatment was performed twice a week, with each application lasting 48 h, followed by a 1-day interval, for more than two weeks.

Fig. 1
figure 1

Kinesio Taping (KT) abdominal attachment method (A) anterior abdomen; (B) lateral abdomen).

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Outcome measurements

Data and the demographic characteristics of women were reviewed before and after RAD treatment, including abdominal measurements at the umbilicus, above and below the umbilicus, distance from the xiphoid to the umbilicus, distance from the umbilicus to the superior margin of the pubic symphysis, and lumbosacral and coccygeal pain. Rectus abdominis separation was recorded as the widest measurements on the left and right sides, and the severity level was assessed according to the measured values (mild ≥ 2–3 cm; moderate ≥ 3–5 cm; and severe ≥ 5 cm)1. The measurements were conducted with the patient in the supine position, with the knees and hips bent, the arms relaxed, and the head raised to the shoulder blade without lifting off the bed. An abdominal ruler was used for the abdominal measurements, which included the abdominal circumference measuring from the umbilicus and 5 cm above and below the umbilicus and the distance from the xiphoid to the umbilicus and the umbilicus to the pubic symphysis (Fig. 2).

Fig. 2
figure 2

Schematic diagram of the abdominal measurements (A) abdominal circumference measurement; (B) measurement from the xiphoid to the umbilicus; and (C) measurement from the umbilicus to the pubic symphysis.

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Statistical analysis

SPSS.25.0 statistical software was used for all statistical analyses. A paired sample T test was used to analyse the variables before and after treatment if the statistical test was normally distributed; otherwise, the Wilcoxon signed-rank test was applied. To compare the two independent samples, a two-sample t-test was used for the normal distribution, and the Wilcoxon rank sum test was used for the non-normal distribution. Using the Shapiro–Wilk test, normality of data was analyzed. The independent-sample t test and chi-square test were used for the subgroup analyses. Spearman’s rank correlation was used for the correlation analysis. Statistical significance was set at 0.05. Statistical descriptive measures were expressed as the mean ± standard deviation, and count data were expressed as the quantity (percent) deviation.

Results

The demographic characteristics of the 138 women included age, height, weight, infant weight, and gestational age at birth. Cesarean section accounted for 69.8% of the births, which was higher than the percentage of vaginal births. Based on the assessment of RAD severity, there were 16, 66, and 56 women with mild, moderate, and severe RAD, respectively, among the 138 women (Table 1).

Table 1 Characteristics of included patients.
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The RAD width was analyzed as a continuous variable. Compared to pre-treatment measurements, the width of RAD decreased from 4.58 ± 1.74 cm to 2.33 ± 0.90 cm after KT treatment with a statistically significant difference (t = 16.713; P < 0.001). A statistically significant difference was also observed in women with mild, moderate, and severe RAD compared to before and after treatment (Table 2). Before treatment, the percentages of women with mild, moderate, and severe RAD were 11.6%, 47.8%, and 40.6%, respectively, whereas the rates after treatment for those with normal, mild, moderate, and severe RAD were 28.3%, 44.2%, 26.8%, and 0.7%, respectively. The Wilcoxon rank sum test results showed a statistically significant difference (Z = − 9.611; P < 0.001) (Table 2; Fig. 3).

Table 2 The comparison of RAD, abdominal circumference, and the pain before and after KT intervention.
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Fig. 3
figure 3

Changes in the level of RAD before and after treatment.

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The abdominal circumference measurements before and after KT treatment revealed a decrease from 82.60 ± 8.50 cm to 77.51 ± 7.90 cm at the umbilicus, from 75.37 ± 8.11 cm to 72.25 ± 7.40 cm above the umbilicus, and from 86.42 ± 7.21 cm to 83.35 ± 6.64 cm below the umbilicus, with statistically significant differences (P < 0.001). A statistically significant difference was also observed in the longitudinal distance from the xiphoid to the umbilicus at the anterior abdomen, which decreased to 14.56 ± 2.11 cm compared to before treatment (16.17 ± 2.88 cm). However, no statistically significant difference was found in the distance from the umbilicus to the pubic symphysis before and after the intervention (Table 2; Fig. 4, 5).

Fig. 4
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The results were measured continuously for six treatments (n = 38).

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The measurement data results from 38 women across six consecutive treatments demonstrated that the RAD width and abdominal circumference showed a significant downward trend after the second treatment, while the distance from the xiphoid process to the umbilicus in the anterior abdomen revealed a downward trend after the third treatment, with no significant change in the distance from the umbilicus to the pubic symphysis (Fig. 4).

Fig. 5
figure 5

One patient with severe RAD received 15 KT treatments (A) pre-treatment; (B) five treatments; (C) 10 treatments; (D) 15 treatments).

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Furthermore, the correlation analysis results of the abdominal dimension and anterior abdominal size revealed that all variables were positively correlated before and after treatment, indicating that KT treatment of the rectus abdominis had a positive synergistic effect on the abdominal circumference change, except for the umbilicus to the pubic symphysis (Table 3).

Table 3 Correlation analysis between abdominal circumference and anterior abdomen before and after treatment.
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To analyse the factors influencing treatment outcomes, the RAD width was divided into two groups that is, ≥ 2 cm and < 2 cm, after treatment, and the differences in the postpartum intervention timing, age, weight gain during pregnancy, abdominal circumference, anterior abdominal longitudinal length, number of births, birthing method, and severity were analyzed before treatment. The results revealed that the severity (P ≤ 0.001) and abdominal circumference below umbilicus (P = 0.024) were statistically different in the two groups. A stratified analysis of women with moderate severity affecting treatment outcomes demonstrated statistically significant differences between the two groups regarding abdominal circumference below the umbilicus (P = 0.039) and longitudinal distance from the xiphoid to the umbilicus (P = 0.029) (Table 4).

Table 4 Statistical analysis of differences in pre-treatment variables for treatment outcomes in the two groups.
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Spearman’s test was used to analyse the correlation between a reduced RAD and number of treatments, timing of postpartum interventions, age, weight gain during pregnancy, number and method of births, abdominal circumference, and longitudinal distance of the anterior abdomen. The results revealed that the decrease in RAD was positively correlated with the number of treatments (P ≤ 0.001) and abdominal circumference below the umbilicus (P = 0.013) (Table 5).

Table 5 Correlation analysis of RAD treatment effect with pretreatment variables.
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Discussion

KT is a treatment method utilized by physiotherapists in clinics. For RAD treatment, possible mechanism included KT’s self-retraction, which provides an avenue for an optimal mechanical repair of the rectus abdominis muscle, supports the RAD self-healing properties, and protects the white line. Secondly, KT can enhance peripheral afferent signals by activating skin receptors, adjusting the central control of muscles, and maintaining muscle tone. Third, KT application can improve the subcutaneous space, thereby increasing blood circulation and lymphatic drainage, providing favorable conditions for tissue repair9,12,13. A randomized clinical trial conducted in the Physical Therapy Department at Wroclaw Medical University revealed that the application of KT tapes using the corrective technique can contribute to RAD reduction in women up to 12 months after birth10. A review included eight studies summarized that in clinic KT is effective for diastasis recti and in improving lumbopelvic spine stability and enhance their quality of life; however, only a few studies were accessible14. A randomized controlled trial evaluated the effects of 4 weeks of KT combined with exercise therapy on abdominal function in women undergoing cesarean section showed that the addition of KT significantly improved abdominal muscle strength and provided greater benefits for abdominal recovery11.

Our retrospective study results demonstrated that women who received KT treatment showed a reduction inRAD width and improvement in RAD severity. We also found that the abdominal circumference and anterior abdominal size decreased after RAD treatment, except for the distance from the umbilicus to the pubic symphysis. This could be attributed to the fact that the lower abdominal circumference increased more during pregnancy, and the postpartum lower abdominal circumference was greater than the upper abdominal and umbilical midabdominal circumference, which may suggest a more severe lower abdominal injury, abdominal wall fat accumulation, and abdominal wall obesity. In this study, Cesarean section accounted for 69.8% of births, which was greater than that of vaginal birth. Cicatrix after Cesarean section can cause stratification and accumulation of fat in the lower abdomen, which may influence recovery15,16. Meanwhile, more women exhibited moderate to severe rectus abdominis dissociation, resulting in more severe abdominal wall dysfunction3. We also observed a downward trend after the third treatment, following six consecutive measurements. Correlation analysis of abdominal circumference indicators before and after treatment revealed a positive correlation, suggesting a synergistic reduction in both anterior and total abdominal circumference, except for the anterior lower abdomen. KT therapy is not only suitable for rectus abdominis separation but also has a therapeutic effect on reducing abdominal circumference.

Analysis of possible factors influencing treatment outcomes revealed a statistically significant difference in changes to the abdominal circumference below the umbilicus in severity between the cured and noncured groups. In the stratified analysis of two treatment outcomes in women with moderate severity, a statistically significant difference was found between the abdominal circumference below the umbilicus and distance from the xiphoid to the umbilicus. However, cured and noncured groups outcomes had no statistical differences were found in the demographic variables, such as age and weight, or in the childbirth-related indicators. The analysis of treatment outcomes revealed that key influencing factors of KT treatment may be related to RAD severity, lower abdominal circumference, and anterior abdomen size. Moreover, changes in the circumference of the lower abdomen are positively correlated with rectus abdominis recovery. Consistent with existing literature, the increase in lower abdominal circumference was correlated with abdominal wall dysfunction severity, and the increase in the lower abdominal circumference is also related to more serious abdominal muscle and fascia injury, which may lead to significant functional sequelae17,18. Furthermore, the number of treatments was positively correlated with RAD recovery.

Our study suggests that KT therapy can enhance RAD recovery, synergistically reduce abdominal circumference, and improve the recovery of abdominal wall function and core function. In clinical practice, KT therapy can also increase gluteal muscle activation bonding methods, improve spinal mechanics, and promote abdominal recovery to a greater extent. Finally, postural and core functions are restored after childbirth19,20,21,22.

This study presents clinical data on KT for the treatment of RAD. Preliminary analysis also showed the effect of KT treatment in promoting RAD recovery and reducing abdominal circumference and anterior abdominal size. Due to the small sample size in this study, the distribution of women across different levels of severity is uneven, making it difficult to conduct a stratified analysis. In future researches, we aim to increase the sample size to establish a control group to account for possible confounding factors, and further demonstrate the efficacy of KT treatment.

Conclusions

Preliminary analysis showed the effect of Kinesio Taping in promoting rectus abdominis diastasis recovery and improving abdominal circumference and anterior abdominal size. Additionally, rectus abdominis diastasis was positively correlated with lower abdominal circumference and anterior abdominal injury. More studys will be needed to confirm clinical validity of the above results.