The objective of this study was to use the finite element (FE) Global Human Body Model Consortium (GHBMC) simplified midsize male human body model to investigate occupant kinematics and potential safety concerns with a large range of recline angles and restraint configurations in frontal crashes. Target postures were obtained by predicting joint centre locations at three recline angles, i.e. 25°, 45°, and 60°, using a seating posture model developed based on volunteer measurements at a wide range of recline angles. A mesh morphing method was used to change the pelvis, lumbar vertebrae, and the surrounding soft tissues of the GHBMC model into the target postures. Three seat models (rigid seat, semi-rigid seat, and an OEM seat), four seatbelt lap belt angles, the presence of an anchor pre-tensioner and dynamic locking tongue (DLT), and the presence of a knee bolster and toe pan were varied in a parametric study under a generic 56 km/h frontal crash pulse. No airbag was used in any of the simulations. Occupant kinematics as well as injury measures were examined for potential safety concerns. Several interesting trends were observed in the simulations. The lap belt angle showed dominant effects on submarining. Although changing the restraints can reduce the submarining risk, there is a clear conflict between submarining and lumbar spine force in highly reclined postures, as cases without submarining were associated with higher lumbar force.