Provided data/ultrasound videos Here we provide ground truth data to validate ultrasound (US) measurement methods that assess shear or deformation of the thoracolumbar fascia (TLF). Studies that have done so are in the instance: Langevin et al. (2011). Reduced thoracolumbar fascia shear strain in human chronic low back pain. BMC Musculoskeletal Disorders, 12, 203. https://doi.org/10.1186/1471-2474-12-203 Weber et al. (2022). The Influence of a Single Instrument-Assisted Manual Therapy (IAMT) for the Lower Back on the Structural and Functional Properties of the Dorsal Myofascial Chain in Female Soccer Players: A Randomised, Placebo-Controlled Trial. Journal of Clinical Medicine, 11(23), 7110. https://doi.org/10.3390/jcm11237110 Brandl et al. (2023). Thoracolumbar fascia deformation during deadlifting and trunk extension in individuals with and without back pain. Frontiers in Medicine, 10, 1177146. https://doi.org/10.3389/fmed.2023.1177146 Brandl et al. (2024). Quantifying thoracolumbar fascia deformation to discriminate acute low back pain patients and healthy individuals using ultrasound. Scientific Reports, 14(1), 20044. https://doi.org/10.1038/s41598-024-70982-7 The data contains ground truth of different velocities and distances from dynamic US measurements of the gel pad simulated the erector spinae muscle and upper tissue layers. For details regarding the gel pads, see Bartsch et al. (2023). Assessing reliability and validity of different stiffness measurement tools on a multi-layered phantom tissue model. Scientific Reports, 13(1), Article 1. https://doi.org/10.1038/s41598-023-27742-wFor this reason, we have developed a customised device based on a linear guide driven by a stepper motor, with which the mimicked tissue layers can be moved with high precision. An explanatory video with detailed information on device setup can be found in the file: Device setup.mp4 Measurements for demographics were taken according to Brandl (2024). Ultrasound measurement of thoracolumbar fascia deformation. Protocols.io. https://dx.doi.org/10.17504/protocols.io.eq2lyjbmwlx9/v1 Measurement uncertainty for distance: +/- 0.002 mm k = 2 (95% confidence interval) and for speed: +/- 0.001 mm k = 2 (95% confidence interval) according to ISO (1993). Guide to the expression of uncertainty in measurement. International Organization for Standardization, Geneva. We further provide an example MATLAB script that demonstrate the use of the ground truth data with the open source image processing software Kinovea, Charmant, J., & contributors. (2023). Kinovea (Version 2023.1.1) Computer software. https://www.kinovea.org Data structure Folder ODS Table Sheets Description TLFD_demographics TLFD_demographics demographics contains the data abbreviations abbreviations and units used in the table TLFD_GT\TLFD_GT_distances TLFD_GT_distances distances contains ground truth distance data and filenames of ultrasound abbreviations abbreviations and units used in the table TLFD_GT\TLFD_GT_speeds TLFD_GT_speeds speeds contains ground truth speed data and filenames of ultrasound abbreviations abbreviations and units used in the table MATLAB complete demo files for speckle tracking analysis with Kinovea MATLAB\Readme detailed instructions for using the MATLAB script