Testing the Association Between Low Back Pain Intensity and Core Muscle Strength in Postpartum Women with Different Delivery Modes: An Analytical Cross-Sectional Study

<b>Background/Objectives</b>: Postpartum women frequently experience nonspecific low back pain (NSLBP), yet the impact of delivery mode on the function of local core muscles, particularly the transversus abdominis (TrA) and lumbar multifidus (LM), is not well understood, limiting the development of targeted rehabilitation strategies. To compare NSLBP intensity and TrA and LM strength in women who underwent cesarean delivery (CD) or vaginal delivery (VD), and to examine the associations between pain intensity and muscle strength. <b>Methods</b>: An analytical cross-sectional study was conducted on 36 women divided into two groups: 18 who underwent CD (Group A) and 18 who underwent VD (Group B). NSLBP intensity was assessed using the visual analogue scale, while TrA and LM strength were measured via a pressure biofeedback unit. <b>Results</b>: The two groups showed non-significant differences in age (<i>p</i> = 0.342), BMI (<i>p</i> = 0.429), or parity (<i>p</i> = 0.894), confirming comparable baseline characteristics. NSLBP intensity was significantly higher in the CD group (<i>p</i> = 0.000), and they exhibited weaker TrA (<i>p</i> = 0.009) strength than the VD group; however, there was a non-significant difference in LM strength (<i>p</i> = 0.602). The Spearman correlation analysis revealed non-significant associations between NSLBP intensity and TrA and LM strength in the CD group (<i>p</i> = 0.702, 0.129, respectively) and in the VD group (<i>p</i> = 0.149, 0.877, respectively). <b>Conclusions</b>: Women undergoing CD experienced higher NSLBP intensities and weaker TrA strength than those undergoing VD, while LM strength remained similar between groups. However, NSLBP intensity showed non-significant associations with TrA or LM strength in either group, suggesting that other biomechanical or neuromuscular factors may contribute to the increased post-CD NSLBP. These findings highlight the need for targeted rehabilitation strategies beyond core muscle strengthening alone.