| Abstract |
| This study aimed to develop “smart” sportswear knitted with strain sensors to detect repetitive elbow and knee flexion and extension movements and examine the relationship between sensor voltage signals and the actual number of repetitions under actual-use conditions. To this end, design criteria were established through theoretical and case studies, as well as analyses of body dimensions and garment deformation associated with joint movements, in order to design and fabricate upper- and lower-body smart sportswear. Subsequently, one adult female participant performed dumbbell curls and lunges; signals from the left and right elbow and knee sensors were analyzed. The results were as follows. First, joint-sensor positional alignment, alignment between garment deformation and sensor strain direction, close-fitting garment structure, sensor dimensions, structural integration, flexible signal transmission, and detachability of the electronic module were identified as design requirements. Second, knitted strain sensors measuring 55 x 165 mm for the posterior elbow region and 60 x 175 mm for the anterior knee region were directly knitted into the garments with zigzag-stitched lead wires and snap-type MCU connections. Third, all four sensors exhibited periodic signal changes, with the voltage decreasing during flexion and increasing during extension. Fourth, in one representative set, ten signal cycles corresponding to ten actual repetitions were visually distinguished for the left and right elbow and knee sensors. These results indicate that the knitted strain sensors could generate periodic voltage signals corresponding to repetitive elbow and knee flexions and extension movements during actual wear. This study is significant for implementing a garment-integrated knit strain sensor system, while considering joint location and clothing deformation direction. The applicability to repetitive movements involving different major joints was also explored. However, this was an exploratory application test with only one participant; and the raw signal cycles were visually examined without a separate reference device for joint-angle measurement or an automated detection algorithm. Therefore, the findings should be considered an exploration of the relationship between joint movement and sensor signals under limited conditions rather than a validation of repetition-counting accuracy or joint-angle measurement performance. |
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| Key Words |
| Knitted Strain Sensor, Smart Sportswear, Garment-integrated Sensor, Joint Movement Monitoring, 니트 스트레인 센서, 스마트 스포츠웨어, 의복 통합형 센서, 관절 동작 모니터링 |
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