Author(s): AKYILDIZ, Z., SEVER, O., YILMAZ, H., ÇIYDEM, Ç., GÜLER, O., SENTÜRK, D., Institution: AFYON KOCATEPE UNIVERSITY, Country: TURKEY, Abstract-ID: 2639

INTRODUCTION:
Linear position transducers are widely used in velocity-based resistance training to quantify barbell kinematics and estimate derived kinetic variables. Although previous research has evaluated earlier GymAware models, the measurement properties of the newly released GymAware RS across various resistance-training conditions, including free-weight exercises, have not yet been independently examined, which may raise questions about its applicability in diverse practical settings.
METHODS:
Eighteen resistance-trained males performed free-weight bench press repetitions at 40%, 60%, and 80% of one repetition maximum across two sessions. Mean velocity, peak velocity, mean force, peak force, mean power, and peak power were simultaneously recorded using GymAware RS and a three-dimensional motion capture system (Qualisys). Device-by-load effects were evaluated using linear mixed models. Agreement was quantified using intraclass correlation coefficients, coefficient of variation, and Bland–Altman analysis to assess systematic and proportional bias. Within- and between-session reliability of the GymAware RS was determined using intraclass correlation coefficients and coefficient of variation.
RESULTS:
Mean velocity showed no significant differences between devices at any load and demonstrated excellent agreement with low measurement error. Mean force differed between systems at 40% of one repetition maximum but not at 60% or 80%. Mean power exhibited systematic differences at 40% and 60%, with smaller discrepancies at 80%. Peak force differences were load-dependent and most evident at 60%. Proportional bias was observed for mean velocity (small), mean power, and peak force, indicating magnitude-dependent differences. Agreement was excellent for velocity, good to excellent for mean force, and moderate to good for power and peak force variables. These differences highlight the importance of understanding each system's measurement principles when interpreting kinetic data for practical applications.
CONCLUSION:
The GymAware RS provides highly accurate and reliable measurements of barbell velocity during the free-weight bench press across moderate to high loads. Differences observed in force and power variables were systematic and load-dependent rather than random. These findings likely reflect fundamental differences in measurement principles between linear position transducers and three-dimensional motion capture systems, which serve as reference methods. Velocity outputs appear directly applicable for monitoring and prescription purposes in velocity-based resistance training. In contrast, derived kinetic variables should be interpreted within the context of the specific measurement system used, as outputs from different technologies may not be directly interchangeable. Overall, the GymAware RS appears well-suited for applied monitoring in free-weight resistance exercise.