Development of a Smart Shoe System Toward Evaluating Curling Skill and Ice Surface Conditions: A Sensor-Embedded Slider for Vibration-Based Characterization of Ice Surface Conditions

In curling, quantitative assessment of ice surface conditions during actual play is challenging, and existing sensor-on-stone approaches cannot simultaneously capture ice-contact vibration and athlete-related measurements. We developed a self-contained wearable slider unit embedding two IMUs (LSM6DSV16X), a wideband accelerometer (IIS3DWB), and plantar pressure sensors in a commercially compatible curling slider. Measurements were conducted with two participants under four ice surface conditions (used pebble, no-pebble, extra-fine, and coarse-fine pebble) at an actual curling hall. The root mean square (RMS) amplitude of the DC-subtracted IIS3DWB Z-axis vibration signal distinguished no-pebble from pebbled ice but did not distinguish among the three pebbled conditions. The spectral centroid of the no-pebble condition was also biased toward higher frequencies, although participant-dependent effects remained among pebbled conditions. The slider acquired plantar-pressure variation during delivery, and an exploratory pooled analysis showed a pattern consistent with greater right/left balance variation in trials with greater MOCAP-derived lateral wobble. Because only two participants were tested and the lateral pressure channels reached the calibration limit, participant-specific validation requires a wider measurement range and additional participants. These results support the feasibility of simultaneous ice-contact vibration and plantar-pressure measurement during curling delivery.