Toward accessible gait analysis: a cross-modal evaluation of performance, cost and clinical validation

Traditional gait analysis is based on laboratory experiments that use motion capture and force plates. While these systems deliver precise results, they also have drawbacks in terms of high cost and lack of portability, motivating research into cost-effective solutions. The following review summarizes approximately 180 recent studies spanning low-cost prototype and commercial gait analysis systems, with commercial systems included as performance benchmarks. The low-cost alternatives reviewed span five modality types: vision-based systems, inertial measurement units (IMUs), electromyography (EMG)-based systems, pressure-sensing systems including smart insoles and flexible sensors, and hybrid multimodal systems. These systems are evaluated along three dimensions: quantitative performance, system cost, and clinical validation. Performance is evaluated based on error rates, reliability, and classification accuracy. At the same time, system costs are reported in the currencies used by the original studies, with USD values referenced where available, acknowledging regional variation in purchasing power and component pricing. Direct comparison across systems is difficult due to heterogeneous evaluation metrics and inconsistent cost reporting; costs span several orders of magnitude from ultra-low-cost prototypes to commercial systems yet remain a poor predictor of performance. The clinical validation of these techniques is conducted mostly on small controlled samples, with studies predominantly from North America, Europe, and East Asia, leaving South Asia, Sub-Saharan Africa, Latin America, and the Middle East substantially underrepresented. No single modality offers all required aspects: IMUs provide high temporal resolution for kinematic parameters, vision-based systems offer rich spatial and kinematic information, pressure-sensing systems including smart insoles capture plantar contact dynamics, EMG-based systems provide complementary neuromuscular information, and hybrid systems improve overall performance at the cost of added complexity. Critically, laboratory performance does not guarantee real-world reliability. This review identifies standardized evaluation, large-scale clinical validation, and cost transparency as key priorities for advancing low-cost gait analysis toward real-world deployment.