From Measurement to Action: A Systematic Review of the Neglected Dimensions of Feedback in IMU based Assessment of Children's Motor Development

Introduction and objectives: Wearable inertial measurement units (IMUs) can objectively assess children's motor competence, yet their raw outputs remain inaccessible to non expert users such as teachers and coaches. The Swain et al.’s (2024) framework specifies three feedback themes—"Grab and Go", "Adjust and Adapt", and "Visualize and Feedback"—that are essential for user centred systems. However, the extent to which existing IMU based studies have addressed these dimensions is unknown. This systematic review aims to determine the extent to which existing IMU based studies have addressed these feedback dimensions and to propose an evidence informed framework for designing user centred feedback systems for teachers and coaches.

Materials and Methods: A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Three databases (Web of Science, IEEE, and Scopus) were searched up to February 2025. Studies were included if they used IMUs to assess fundamental movement skills in children (4–12 years) and reported quantitative outcomes. Methodological quality was assessed using the JBI checklist. Each study was mapped against the 14 sub dimensions of the Swain framework and was classified as Type I (neglect: no feedback) or Type II (poor performance: feedback attempted but inadequate for non experts).

Results: Twenty three studies were included. Nineteen (83%) were Type I —no feedback was provided. Four (17%) were Type II —feedback was limited to raw numbers (e.g., jump height) or graphs requiring expert interpretation. No study addressed personalisation (A1–A3), multimodal feedback (V2–V4), or referral alerts (R1–R2). Six persistent gaps were identified: Lack of actionable feedback, personalisation, multimodality, avatar based visualisation, referral mechanisms, and emotional engagement.

Discussion and Conclusions: IMU based motor assessment has prioritised measurement accuracy while systematically neglecting the feedback needs of teachers and coaches. A seven step evidence informed framework is proposed, including hardware simplification (≤3 IMUs), developmental level personalisation, stepwise multimodal feedback, teacher referral alerts, field validation in schools, and open science practices. Closing the feedback gap requires a cultural shift from engineer centred validation to a teacher centred design.