Past studies have found that a pressure based injury risk function was the best predictor of liver injuries due to blunt impacts. In an effort to expand upon these findings, this study investigated the biomechanical responses of the abdomen of post mortem human surrogates (PMHS) to high-speed seatbelt loading and developed external response targets in conjunction with proposing an abdominal injury criterion. A total of seven unembalmed PMHS, with an average mass and stature of 71 kg and 174 cm respectively were subjected to belt loading using a seatbelt pull mechanism, with the PMHS seated upright in a free-back configuration. A pneumatic piston pulled a seatbelt into the abdomen at the level of the umbilicus with a nominal peak penetration speed of 4.0 m/s. Pressure transducers were placed in the re-pressurized abdominal vasculature, including the inferior vena cava (IVC) and abdominal aorta, to measure internal pressure variation during the event. Jejunum tear, colon hemorrhage, omentum tear, splenic fracture and transverse processes fracture were identified during post-test anatomical dissection. Peak abdominal forces ranged from 2.8 to 4.7 kN. Peak abdominal penetrations ranged from 110 to 177 mm. A force-penetration corridor was developed from the PMHS tests in an effort to benchmark ATD biofidelity. Peak aortic pressures ranged from 30 to 104 kPa and peak IVC pressures ranged from 36 to 65 kPa. Updated pressure based abdominal injury risk functions were developed for vascular Ṗmax and Pmax*Ṗmax.