Agreement Between Kinovea And The Open Barbell System For Barbell Velocity And Range Of Motion

Abstract

PURPOSE: The aim of this study was to examine the degree to which Kinovea video analysis software and a linear position transducer, the Open Barbell System (OBS), agree for measurements of average (ACV) and peak concentric velocity (PCV), as well as concentric range of motion (ROM) during the free-weight back squat and bench press exercises. METHODS: Sixteen males (age: 23.6±2.8yrs, body mass: 82.0±12.2kg, height: 171.8±7.5cm, training age: 7.0±3.6yrs) performed a bench press and squat one-repetition maximum (1RM) in the first session. Then, in 3 different sessions subjects performed 3 (sets) X 1 (repetition) at 60% and 80% of 1RM. On each repetition, ACV, PCV, and ROM were assessed via both Kinovea and OBS. A smartphone was used to obtain videos from the lateral aspect that were later uploaded for analysis via Kinovea software, while the OBS was attached to the barbell via a cord and all outcomes were displayed on the unit in real time. Paired t-tests, intraclass correlation coefficients (ICCs), Bland-Altman plots, and folded empirical cumulative distribution plots (mountain plots) were used to analyze results. RESULTS: Due to recording errors 348 out of a possible 352 repetitions were recorded. Paired t-tests revealed significant differences between measurement systems in all outcome variables for both the squat and bench press (p<0.01). ICCs for the squat were: 0.929 (ACV), 0.913 (PCV), and 0.188 (ROM). ICCs for the bench press were: 0.930 (ACV), 0.929 (PCV), and 0.683 (ROM). Large limits of agreement were observed in all Bland-Altman plots and visual inspection of the mountain plots revealed deviation from the zero-difference line and long tails in all plots denoting a lack of agreement between devices. CONCLUSION: In summary, the Kinovea software and OBS do not agree for measurement of ACV, PCV, and ROM during the squat and bench press. The OBS is a validated device versus a motion capture system, therefore we do not recommend Kinovea for these outcomes.