Ultrasound Imaging of the Abdominal Wall and Trunk Muscles in Patients with Achilles Tendinopathy versus Healthy Participants

Purpose: To compare and quantify with ultrasound imaging (USI) the inter-recti distance (IRD), rectus abdominis (RA), external oblique (EO), internal oblique (IO), transversus abdominis (TrAb), and multifidus thickness and the RA and multifidus cross-sectional area (CSA) between individuals with and without chronic mid-portion Achilles tendinopathy (AT). Methods: A cross-sectional study. A sample of 143 patients were recruited and divided into two groups: A group comprised of chronic mid-portion AT (n = 71) and B group composed of healthy subjects (n = 72). The IRD, RA, EO, IO, TrAb, and multifidus thickness, as well as RA and multifidus CSA, were measured by USI. Results: USI measurements for the EO (p = 0.001), IO (p = 0.001), TrAb (p = 0.041) and RA (p = 0.001) thickness were decreased as well as IRD (p = 0.001) and multifidus thickness (p = 0.001) and CSA (p = 0.001) were increased for the tendinopathy group with respect the healthy group. Linear regression prediction models (R2 = 0.260 − 0.494; p < 0.05) for the IRD, RA, EO, and IO thickness (R2 = 0.494), as well as multifidus CSA and thickness were determined by weight, height, BMI and AT presence. Conclusions: EO, IO, TrAb, and RA thickness was reduced and IRD, multifidus thickness and CSA were increased in patients with AT.