Research Review: Induced Acceleration Analysis
Research Review: Induced Acceleration Analysis
Model-bounded review guide for induced acceleration analysis
This page collects sources and defines the minimum record for reviewing how biomechanical models assign acceleration terms to generalized forces, contact, gravity, velocity terms, and residuals.
The current page does not reproduce each paperβs engine, solver, model, or residual evidence. Study summaries without the complete record below are therefore historical context, not qualified golf, pitching, clinical, or motor-control conclusions.
An induced-acceleration attribution is a term ledger for a declared model at a declared state. It is not a unique causal history. A publishable result must identify all of the following:
- Model and revision: segment and actuator definitions, parameter set, generalized coordinates, reference frame, output point or task metric, and the state at which the mass matrix is evaluated.
- Computation: engine, solver, and revision; constraint handling; contact model and active contact mode; integration or frozen-state procedure; and numerical tolerance plus closure error.
- Attribution convention: the complete force partition, including sign conventions, passive and applied terms, constraint reactions, and residual treatment. Reassigning a residual between two terms changes their reported contributions while leaving their sum unchanged.
- Identifiability contract: the measurements or assumptions that identify each generalized-force term and the output projection. An algebraic term contribution does not by itself identify anatomical source, neural intent, necessity, sufficiency, or intervention effect.
If any field is absent, label the result unsupported or unqualified. A cross-engine comparison must report an unavailable state as unsupported or unqualified; agreement on one output, or silence about an unsupported state, does not establish solver parity.
Counterexamples to Unique Attribution
- Coordinate representation: under a constant change of generalized coordinates \(q=Tz\), the same dynamics are represented by \(M_z=T^\mathsf{T}M_qT\) and \(Q_z=T^\mathsf{T}Q_q\). The component values of \(\ddot z=M_z^{-1}Q_z\) generally differ from those of \(\ddot q=M_q^{-1}Q_q\), even though \(T\ddot z=\ddot q\). A generalized- acceleration component is therefore not coordinate-invariant causal truth.
- Force partition: if \(Q=Q_A+Q_B\), then for any residual allocation \(r\), \(Q=(Q_A+r)+(Q_B-r)\). The reported terms \(M^{-1}Q_A\) and \(M^{-1}Q_B\) change, while the total acceleration does not. The partition must be declared and justified before a term is interpreted.
An intervention claim requires a separate governed counterfactual that re-solves constraints and contact and states what is held fixed. The frozen- state algebra alone supports neither a unique cause nor an anatomical or behavioral prescription.
Current Scope
Induced acceleration analysis is relevant to AffineDrift because it computes a term ledger for a declared biomechanical model. Different coordinates, frames, outputs, constraints, contact models, force partitions, muscle-force estimates, solvers, and residual allocations can change the reported terms without changing the total motion represented by the model.
Current Source Links
Review Questions
- Which accelerations are decomposed: joint, segment, center-of-mass, or task-space accelerations?
- Which inputs are separated: muscle forces, joint torques, ground reaction forces, gravity, or intersegmental terms?
- Does the paper use experimental measurements, simulation, or both?
- How sensitive are the conclusions to the model and force-estimation method?
- Does the result bear directly on golf mechanics, or is it a transferable method from another movement domain?