Validation of a Novel Wearable Inertial Measurement Unit for Assessing Barbell Velocity and Power Output During Olympic Weightlifting Lifts in Strength-Trained Individuals

Velocity-based training (VBT) has emerged as an essential methodology for optimizing neuromuscular adaptations and monitoring mechanical outputs during resistance training. While linear position transducers and optoelectronic motion capture systems serve as laboratory gold standards, their cost and tethered nature limit practical application in dynamic Olympic weightlifting movements. This study validated a novel 9-axis wearable inertial measurement unit (IMU; sampling at 500 Hz) against a 10-camera 3D optoelectronic motion capture system (250 Hz) for measuring barbell mean velocity (MV), peak velocity (PV), mean power (MP), and peak power (PP). Twenty-two strength-trained athletes (14 males, 8 females; mean age: 24.6 ± 3.8 years) performed the snatch and clean and jerk across progressive loads (60%, 70%, 80%, and 90% of one-repetition maximum [1RM]). Concordance was assessed using intraclass correlation coefficients (ICC_2,1), Bland-Altman limits of agreement (LoA), Pearson correlation coefficients (r), and mean absolute percentage error (MAPE). The IMU demonstrated excellent concurrent validity across all loads for MV (ICC = 0.95–0.98; MAPE < 3.2%; bias: -0.01 to 0.02 m/s) and PV (ICC = 0.93–0.97; MAPE < 4.1%). Power metrics exhibited high agreement (MP: ICC = 0.91–0.96; PP: ICC = 0.89–0.94), with slight underestimation at 90% 1RM during the second pull. These findings establish that the evaluated IMU provides a valid, reliable, and portable alternative to tethered tracking devices for real-time monitoring of Olympic weightlifting kinematics and kinetics in high-performance environments.