Journal article
Criterion Validity, and Interunit and Between-Day Reliability of the FLEX for Measuring Barbell Velocity During Commonly Used Resistance Training Exercises
Journal of Strength and Conditioning Research, Vol.34(6), pp.1519-1524
2020
PMID: 32459410
Abstract
The aim of this study was to assess the criterion validity, interunit reliability (accounting for technological and biological variance), and between-day reliability of a novel optic laser device (FLEX) for quantifying mean concentric velocity. To assess the validity against a three-dimensional motion capture system and interunit reliability with both technological and biological variation, 18 men and women completed repetitions at 20, 40, 60, 80, 90, and 100% of one repetition maximum in the free-weight barbell back squat and bench press. To assess interunit (technological only) reliability, a purpose-built, calibrated rig completed a set protocol with 2 devices. To assess between-day reliability of the technology, the same protocol was repeated 21 days later. Standardized bias, typical error of the estimate (TEE; %), and Pearson's correlation coefficient (r) were used to assess validity, whereas typical error and coefficient of variation (CV%) were calculated for reliability. Overall, TEE (±90 CL) between the FLEX and criterion measure was 0.03 (±0.004) and 0.04 (±0.005) m·s in the back squat and bench press, respectively. For measures of reliability, overall interunit technological variance (CV% [± 90% confidence interval]) was 3.96% (3.83-4.12) but increased to 9.82% (9.31-10.41) and 9.83% (9.17-10.61) in the back squat and bench press, respectively, when biological variance was introduced. Finally, the overall between-day reliability was 3.77% (3.63-3.91). These findings demonstrate that the FLEX provides valid and reliable mean concentric velocity outputs across a range of velocities. Thus, practitioners can confidently implement this device for the monitoring and prescription of resistance training loads.
Details
- Title
- Criterion Validity, and Interunit and Between-Day Reliability of the FLEX for Measuring Barbell Velocity During Commonly Used Resistance Training Exercises
- Authors
- Jonathon Weakley (Corresponding Author) - Leeds Beckett UniversityDaniel Chalkley - Australian Catholic UniversityRich Johnston - Australian Catholic UniversityAmador Garcia-Ramos - Universidad Católica de la Santísima ConcepciónAndrew Townshend - Australian Catholic UniversityHarry Dorrell - University of LincolnMadison Pearson - Australian Catholic UniversityMatthew Morrison - Australian Catholic UniversityMichael H Cole - Australian Catholic University
- Publication details
- Journal of Strength and Conditioning Research, Vol.34(6), pp.1519-1524
- Publisher
- Lippincott Williams & Wilkins
- Date published
- 2020
- DOI
- 10.1519/JSC.0000000000003592
- ISSN
- 1533-4287
- PMID
- 32459410
- Organisation Unit
- Centre for Human Factors and Sociotechnical Systems
- Language
- English
- Record Identifier
- 991128802502621
- Output Type
- Journal article
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web Of Science research areas
- Sport Sciences