###### Abstract  
The aim of the present study was to evaluate and compare with rehabilitative ultrasound imaging (RUSI) abdominal wall muscle thickness and interrecti distance (IRD) between elite and amateur basketball players. A sample of 32 basketball players (age: 23.0 \(\pm\) 8.5; height: 1.89 \(\pm\) 14.25 m; weight: 86.6 \(\pm\) 15.5 kg; body mass index: 22.8 \(\pm\) 2.6 kg/m\({}^{2}\)) was divided in two groups: professional elite and amateur players. A diagnostic ultrasound tool with a 7-14 MHz range linear transducer was used for B mode ultrasound imaging. Ultrasound images of the external oblique (EO), internal oblique (IO), transversus abdominis (TrAb), and rectus anterior (RA) muscles as well as IRD were measured and analyzed by ImageJ software. Statistically significant differences (_p_ < 0.05) with greater height, weight, and Nijmegen scores were shown in favor of the elite basketball players compared to the amateur basketball players. Ultrasound measurements of the abdominal wall muscles showed statistically significant differences (_p_ < 0.05) for increased IRD and left TrAb thickness and decreased right and left EO thickness in favor of the elite versus amateur basketball players. The rest of the measurements did not show any statistically significant differences (_p_ > 0.05). Increased IRD and TrAb thickness and reduced EO thickness may be shown in elite versus amateur basketball players. abdominal muscles; basketball; diagnostic imaging; ultrasonography 0000-0001-5000-0000-0000-0000-0000-0000-00000-0000-00000-00000-00000-00000-00000-000000-0  
injuries [4]. Regarding the lower limb, a recent study found decreased thickness in the vastus medialis muscle in patients with knee osteoarthritis [5]. Additionally, peroneus longus CSA was reduced in patients with lateral ankle sprains compared with patients without this condition [6]. CSA and thickness of the abductor hallucis and flexor hallucis brevis were reduced in patients with hallux valgus [7]. With respect to the temporomandibular region, the function of the masseter, temporalis, and sternocleidomastoid muscles has been linked with temporomandibular joint disorders [8]. [PERSON] et al. [9; 10] showed that monitoring deep cervical flexor muscles with ultrasonography may be carried out during training programs for patients with chronic neck pain. In the trunk region, multifidus and abdominal wall muscles have been related to lumbopelvic pain (LPP) [11; 12]. Muscles of the abdominal wall act to support and provide stability to the spine [13]. These muscles form a ring surrounding the spine, with the rectus abdominis (RA) in the midline and laterally three overlapping layers comprising the external oblique (EO), internal oblique (IO), and transversus abdominis (TrAb) [12]. These muscles work in a coordinated system in conjunction with the diaphragm, lumbar multifidus, and pelvic floor muscles to transfer loads around the trunk and balance abdominal pressure [13]. In patients without LPP, RA, OI, OE, and TrAb represent 35.0%, 28.4%, 22.8%, and 13.8% of cumulative abdominal thickness, respectively [14]. Moreover, [PERSON] et al. [12] found thinner RA and thicker perimuscular vertebral connective tissue in individuals with LPP. All these measures may be very useful to assess muscle changes that could exist with pathology [15]. Excellent interexaminer reliability (intraclass correlation coefficient (ICC) = 0.92-0.99) has been shown for RUSI thickness measurements of abdominal wall muscles [12]. The relationship between abdominal wall muscle thickness measured with magnetic resonance imaging (MRI) and RUSI showed appropriate validity (ICC = 0.84-0.95) [15; 16]. The inherent variability of the measurement location and the respective change in RUSI thickness measurement of the abdominal wall have shown a standard error of measurement (SEM) of 0.2-0.4 mm and a minimum detectable change (MDC) of 0.6-1.1 mm [12].