Data about abdominal wall function in patients with incisional hernias (IH) are limited. Abdominal Wall Reconstruction (AWR) could be beneficial for the improvement of this function. The goal of the study was to evaluate if the abdominal wall function was restored after transversus abdominis muscle release (TAR). We performed a prospective case-control study of 59 patients with IH equal or larger than 10cm in their width undergoing AWR via TAR with mesh reinforcement and complete linea alba restoration. With two simple physical tests-Trunk Raising (TR) and Double Leg Lowering (DLL), we clinically assessed, preoperatively, 1month and 1year postoperatively the functionality of the abdominal wall (flexion). Patients were compared with a control group (n = 57) with an intact abdominal wall undergoing visceral surgery through a midline laparotomy. There were no differences between the groups in terms of sex and mean age. In the study group, TR demonstrated an increase from 1.93 preoperatively to 2.44 at 1month and 4.27, respectively, at 1year postoperatively (p < 0.001). DLL was improved from 2.067 to 4.37 at 1year postoperatively (p = 0.016). In the control group, surgery resulted in a decrease of truncal flexion. At 1year postoperatively, the abdominal wall function for study group patients was almost identical with that the functionality of the control group featuring an intact abdominal wall (TR 4.26 vs 4.33 p = 0.532; DLL 4.42 vs 4.21 p = 0.193). AWR via TAR for large IH specifically improved long-term abdominal wall muscular function.