Nanomaterial-Enabled Flexible Wearable Sensors for Sports Monitoring and Rehabilitation: Material Architectures, Interface Design, and Signal Reliability

Flexible wearable sensors increasingly use nanomaterials and nanoscale interfaces to acquire biomechanical, electrophysiological, and biochemical signals during sports and rehabilitation, where repeated deformation, perspiration, and variable body contact challenge measurement stability. This review examines how the nanomaterial architecture and body–sensor interface design influence signal reliability under dynamic operating conditions. Carbon nanomaterials, MXenes, conductive polymers, metallic nanostructures, and soft nanocomposites are discussed together with matrices and fibrous supports that regulate their mechanical and chemical interfaces. Emphasis is placed on the links between nanoarchitecture, transport behavior, interfacial coupling, and major transduction routes. Representative applications in motion monitoring, exercise physiology, sweat analysis, and rehabilitation are then assessed in terms of signal stability and physiological interpretability. The literature indicates that sensitivity alone is an incomplete measure of wearable performance because working range, hysteresis, adhesion, sampling variability, and calibration drift often become limiting factors under repeated use. Reliable sensing depends on preserving a stable relationship between the target stimulus and sensor output across realistic operating conditions. Future work should focus on robust nanoarchitectures, adaptive body–sensor interfaces, application-specific calibration, and validation under combined mechanical and environmental loading.