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Test-Retest Reliability of a Commercial Linear Position Transducer (GymAware PowerTool) to Measure Velocity and Power in the Back Squat and Bench Press

Orange, Samuel T.1,2; Metcalfe, James W.1,2; Marshall, Phil1; Vince, Rebecca V.1; Madden, Leigh A.3; Liefeith, Andreas2

The Journal of Strength & Conditioning Research: June 25, 2018 - Volume Publish Ahead of Print - Issue - p
doi: 10.1519/JSC.0000000000002715
Original Research: PDF Only

Orange, ST, Metcalfe, JW, Marshall, P, Vince, RV, Madden, LA, and Liefeith, A. Test-retest reliability of a commercial linear position transducer (GymAware PowerTool) to measure velocity and power in the back squat and bench press. J Strength Cond Res XX(X): 000–000, 2018—This study examined the test-retest reliability of the GymAware PowerTool (GYM) to measure velocity and power in the free-weight back squat and bench press. Twenty-nine academy rugby league players (age: 17.6 ± 1.0 years; body mass: 87.3 ± 20.8 kg) completed 2 test-retest sessions for the back squat followed by 2 test-retest sessions for the bench press. GYM measured mean velocity (MV), peak velocity (PV), mean power (MP), and peak power at 20, 40, 60, 80, and 90% of 1 repetition maximum (1RM). GYM showed good reliability (intraclass correlation coefficient [ICC] and standard error of measurement percentage, respectively) for the measurement of MV at loads of 40 (0.77, 3.9%), 60 (0.83, 4.8%), 80 (0.83, 5.8%), and 90% (0.79, 7.9%) of 1RM in the back squat. In the bench press, good reliability was evident for PV at 40 (0.82, 3.9%), 60 (0.81, 5.1%), and 80% (0.77, 8.4%) of 1RM, and for MV at 80 (0.78, 7.9%) and 90% (0.87, 9.9%) of 1RM. The measurement of MP showed good to excellent levels of reliability across all relative loads (ICC ≥0.75). In conclusion, GYM provides practitioners with reliable kinematic information in the back squat and bench press, at least with loads of 40–90% of 1RM. This suggests that strength and conditioning coaches can use the velocity data to regulate training load according to daily readiness and target specific components of the force-velocity curve. However, caution should be taken when measuring movement velocity at loads <40% of 1RM.

1Sport, Health and Exercise Science, School of Life Sciences, University of Hull, Hull, United Kingdom;

2School of Sport, York St John University, York, United Kingdom; and

3Center of Biomedical Research, School of Life Sciences, University of Hull, Hull, United Kingdom

Address correspondence to Samuel T. Orange,

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