A Size-Adjustable Instrumented Track to Measure Vertical Ground Reaction Forces: A Validation Study

Force plates are widely used in sports science to measure ground reaction forces (GRFs). However, their use in ecological conditions is limited by their restricted recording measurement area. Recently, a size-adjustable track instrumented with force sensors has been developed to measure vertical GRFs (vGRFs) over large perimeters. The aim of this study was to evaluate the accuracy and repeatability of this instrumented track (IT). The evaluation was conducted through a two-step protocol: 1) a static protocol assessing the accuracy and repeatability of force sensors composing the IT and 2) an ecological protocol aiming to assess values obtained while running on both a reference force plate (RFP) and a three-sensor IT configuration. Results from the static protocol demonstrated an excellent agreement between the reference force sensor and the IT sensors ( ${p} \lt 0.001$ , ICC ${}_{\text {(}{3},{1}\text {)}} \gt 0.99$ ). Force measured from the IT sensors showed high accuracy with an average bias of 1.27 N, corresponding to a ratio limit of agreement (LOA) of 0.3%, and a repeatability error within 2 N. For the ecological protocol, there was also an excellent correlation between the vGRF running parameters measured by the RFP, and the IT ( ${p} \lt 0.001$ , ICC ${}_{\text {(}{3},{1}\text {)}} \gt 0.98$ ), reinforced high accuracy results. Moreover, a “Minimal Detectable Changes” analysis indicated that IT can accurately quantify all running patterns. This study demonstrated that force sensors integrated into the IT may be used to assess running patterns over a large area, expanding the scope of dynamic analysis in various applications.