Soft tissue mechanics reproducibility and prediction plan

Approved analysis plan for a secondary analysis of porcine spinal-cord mechanical measurements. The study will audit how explicit constitutive, fixation, and indentation-processing choices affect held-out force predictions, and will release a checked mechanical specification and reproducibility flags. It specifies a primary bulk prediction test and secondary mapping and sensitivity-envelope tests, including fixed rules for failure and non-evaluability. The plan was approved before constitutive tissue fitting. Earlier exploratory data summaries and source-equation discrepancies were already known and are not retrospectively preregistered. This deposit contains the approved plan, machine-readable protocol and prediction rules, and content hashes; it contains no empirical model results or original raw dataset. Source dataset: https://doi.org/10.5281/zenodo.17152951. Source article: https://doi.org/10.1016/j.actbio.2026.04.036. Numerical forward-model verification is required before empirical fitting. This is a timestamped analysis-plan archive, not a registered report or completed validation study. The deposit is the plan and specification subset; the Availability section also describes separate project review records that are not included in this public archive.