README.txt

Title: Supplementary materials for lateral pinch force simulations using constrained and contact-based models

This repository contains the supplementary materials associated with the manuscript:

Sancho-Bru, J.L. et al. Influence of interaction formulation on lateral pinch force estimation using a musculoskeletal hand model. Biomechanics, under review.

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OVERVIEW

This dataset includes the scripts and processed data required to reproduce the simulations and analyses presented in the study. It is organized into two main components:

1. Simulation scripts (constrained and contact-based models)
2. Processed datasets derived from simulation outputs, including aggregated results and interpolated time-series data

All scripts are written in MATLAB and rely on OpenSim for musculoskeletal simulations.

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FOLDER STRUCTURE

* constrained_model/
  MATLAB scripts and associated files required to run the constrained optimization and forward-dynamics simulations.

* contact_model/
  MATLAB scripts and associated files required to run forward-dynamics simulations with explicit contact modeling under different friction conditions.

* processed_data/
  Processed datasets used to generate the results reported in the manuscript, including both summary metrics and interpolated time-series data.

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SIMULATION SCRIPTS

The folders `constrained_model` and `contact_model` contain batch scripts that:

* run multiple simulations of the lateral pinch task,
* generate muscle activation patterns,
* perform forward-dynamics simulations,
* and record computational performance metrics.

These scripts are based on the ARMS hand and wrist model by McFarland et al., with modifications described in the manuscript.

Users must cite both the present study and the original ARMS model publication when using these materials.

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PROCESSED DATASETS

The `processed_data` folder contains Excel files with the processed data used to generate the figures and tables reported in the manuscript. Each file corresponds to a specific analysis:

* F_and_activations_50_runs.xlsx
  Muscle activation patterns obtained from the constrained simulations (50 runs), together with the corresponding pinch force values. Includes identification of top-performing solutions and best solutions within groups of ten simulations.
  (Corresponds to Figures 1–2)

* contact_loss_summary.xlsx
  Summary of contact loss events in the contact-based simulations, including time of contact loss and validity indicators at different time instants.
  (Corresponds to Results Section 3.2)

* stabilization_summary.xlsx
  Stabilization times of the normal force component, including per-simulation values and aggregated statistics (median, IQR, percentiles) for different models and time windows.
  (Corresponds to Figures 3–4 and Table 1)

* posture_change_summary.xlsx
  Changes in joint angles from simulation start to stabilization, including global and joint-level metrics.
  (Corresponds to Table 2)

* similarity_summary_mu_0p29.xlsx

* similarity_summary_mu_1p0.xlsx
  Differences in force and joint angles between constrained and contact-based simulations for different comparison instants, reported per simulation and as aggregated statistics.
  (Corresponds to Figures 5–7)

* computational_cost_summary.xlsx
  Execution times for optimization and forward-dynamics simulations, including per-simulation values and aggregated statistics.
  (Corresponds to Table 3)

* force_time_series_interpolated.xlsx
  Interpolated time series of the normal force component (Y direction) for constrained and contact-based simulations. Data are resampled onto a common time grid and include contact simulations at t = 0.50 s for both friction conditions (μ = 0.29 and μ = 1.0).
  These data support the temporal analyses of force evolution and stabilization.

* joint_angles_time_series_interpolated.xlsx
  Interpolated time series of joint-angle trajectories for constrained and contact-based simulations. Data are resampled onto a common time grid and include contact simulations at t = 0.50 s for both friction conditions (μ = 0.29 and μ = 1.0).
  These data support the analysis of postural evolution and similarity metrics.

All quantities are expressed in SI units unless otherwise specified (e.g., joint angles in degrees). Variable names in each file follow the notation used in the manuscript.

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REQUIREMENTS

To run the simulation scripts, the following software is required:

* MATLAB (with standard numerical and optimization toolboxes)
* OpenSim (with MATLAB API support)

Users must ensure that OpenSim is correctly installed and configured for use with MATLAB.

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NOTES

* The datasets provided correspond to processed results used in the manuscript.
* The interpolated time-series files correspond to post-processed simulation outputs resampled onto a common time grid and do not represent raw OpenSim output files.
* Raw simulation outputs are not included due to their size but are available from the authors upon reasonable request.
* All paths in the scripts are defined using relative directories to facilitate portability.

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CONTACT

For questions regarding the dataset or simulations, please contact the corresponding author.

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