Background: Pressure ulcers are a common occurrence in the sacrum and are frequently associated with deep tissue injury. Research has demonstrated that compression and mechanical strain contribute to tissue damage and can be employed to assess the risk of injury. Despite the existence of several finite element models based on this evidence, the experimental evaluation of localized tissue strain is rarely addressed. Methods: The objective of this study is to present a proof-of-concept protocol for creating subject-specific finite element models of sacral soft tissues under compressive loading and to compare the model predictions with experimental data based on Digital Volume Correlation of MRI data. The data was collected from one asymptomatic volunteer in four loading conditions (vertical loading of 4.3 N, 6.1 N, 8 N and 11.9 N). Findings: A comparison of DVC-derived tissue displacements with the Finite Element simulations demonstrated accurate estimations for maximum values and displacement distribution fields for all load cases, with less than 5 % discrepancy for load configurations L1-L3 and 7 % for load configuration L4. Concerning shear strains, it was observed that there were significant differences between the DVC-derived experimental tissue shear strains and the simulation predictions when generic constitutive parameters were used. The highest difference was 43 % for the highest load configuration (11.9 N). Interpretation: These results demonstrate that incorporating personalized tissue properties substantially improves model fidelity, highlighting the potential of combined imaging, mechanical testing, and FE modelling for individualized risk assessment of deep tissue injury.