Residual Stiffness Model

A testable framework for sequence-sensitive mechanics in collagenous soft tissue.

This paper asks a simple mechanical question: if two matched deformation sequences are applied in different orders, do they leave tissue in the same final state or not? The proposed framework tests whether collagenous soft tissue preserves sequence-dependent residual stiffness using a within-subject crossover design and shear-wave elastography.

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Draft — March 2026

Why This Model Matters

The Core Problem

Collagenous tissues are known to be history-dependent, but most models focus on cumulative loading rather than asking whether loading order itself produces different residual states.

The Central Claim

The paper proposes that two matched deformation sequences — A then B, and B then A — may leave the same tissue region in measurably different post-sequence stiffness states.

The Experimental Test

A within-subject crossover protocol is proposed using controlled multimodal loading and shear-wave elastography to compare post-AB and post-BA residual stiffness.

Why It Matters

If supported, sequence-dependent residual mechanics would matter for soft tissue modeling, manual therapy sequencing, and rehabilitation design. If not supported, the field gains a clear empirical boundary.

The Sequence Question

The framework isolates one unresolved question: given two controlled deformation modes with matched total loading budgets, does reversing the order change the final mechanical state? In this paper, the key comparison is AB versus BA under identical magnitude, duration, and cycle count.

The model does not require commitment to any single microscopic explanation. It tests only whether order-dependent residual mechanics are detectable at a clinically accessible scale.

The Core Hypothesis

Matched deformation sequences AB and BA, applied to collagenous soft tissue under controlled conditions, may produce measurably different post-sequence residual stiffness states.