Validity and Reliability of StriveTM Sense3 for Muscle Activity Monitoring During the Squat Exercise

Background: Recent innovations in surface electromyographic (sEMG) technology have enabled the measurement of muscle activity using smart textiles. Objective: In this study, the StriveTM Sense3 performance monitoring system is evaluated against a research-grade system, NoraxonTM, in measuring activity during the back squat exercise. Method: Seventeen participants performed three total trials of the squat exercise with a progressive load for individual trials equal to 30%, 60%, and 80% of their estimated maximum 1RM (one-repetition maximum). sEMG measurements from the rectus femoris were captured for the left and right leg by both systems. Pearson product-moment correlation coefficient (r) and intraclass correlation coefficient (ICC) values were computed for each trial to assess concurrent validity and interrater reliability of the StriveTM Sense3 device. Additionally, five coaches at the collegiate- and professional-level of Men’s Basketball speak from an autoethnographic frame to the findings from this study. Results: Results ranged from “Poor” to “Excellent” validity and “Poor to Moderate” to “Excellent” reliability, with a majority of trials achieving “Good” or better results across all loads [93% trials: r >= 0.7; 87% trials: lower ICC 95% CI bound >= 0.75 (absolute sEMG); 98% trials: lower ICC 95% CI bound >= 0.75 (normalized sEMG)]. Higher validity and reliability for medium and heavy loads were observed in comparison to the light load, and several outliers indicate the need for coaches to lubricate sensors and ensure proper fit to collect accurate data. Conclusion: Examining results alongside practitioner feedback indicate the StriveTM Sense3 system is capable of tracking sEMG activity in comparison to a research-grade system.