Validity and Within-Device Reliability of the Metric Application for Assessing Barbell Velocity and Displacement
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Authors
Puppyn, NFT
Hofmeyr, S
Brughelli, M
Amdi, CH
Supervisor
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Journal Article
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SAGE Publications
Abstract
This study evaluated the validity and within-device reliability of the Metric smartphone application compared to a linear position transducer (LPT). Twenty-five resistance-trained participants (19 male, 6 female) completed incremental loading one-repetition maximum (1RM) assessments in the back squat, bench press, and deadlift. Mean concentric velocity (MCV) and displacement (CD) were measured simultaneously by two Metric devices and one GymAware LPT. The Metric application detected 94.3% of repetitions (F1-score: 0.971) compared to GymAware's 99.5% (F1-score: 0.997). Within-device reliability of Metric varied by exercise: highest in squat (MCV: ICC = 0.994, CV = 3.83%, SDC = 0.05 m/s [4.27% of 1RM]; CD: ICC = 0.991, CV = 1.53%, SDC = 0.02 m), then bench press (MCV: ICC = 0.981, CV = 7.57%, SDC = 0.08 m/s [6.38% of 1RM]; CD: ICC = 0.974, CV = 3.53%, SDC = 0.02 m), and lowest in deadlift (MCV: ICC = 0.941, CV = 13.29%, SDC = 0.13 m/s [14.05% of 1RM]; CD: ICC = 0.753, CV = 27.16%, SDC = 0.10 m). However, Metric did not meet our predetermined reliability criteria for velocity trackers (ICC ≥ 0.997, CV ≤ 3.5%). Substantial-to-perfect agreement between Metric and GymAware was found for squat MCV (CCC = 0.981–0.993), but only poor-to-moderate agreement for bench press and deadlift MCV (CCC = 0.866–0.946), and poor agreement across all exercises for CD (CCC < 0.768). While Metric offers a cost-effective and user-friendly alternative to LPTs, it cannot currently be recommended for research or practice where high precision is required.Description
Keywords
4201 Allied Health and Rehabilitation Science, 42 Health Sciences, Women's Health, 11 Medical and Health Sciences, 17 Psychology and Cognitive Sciences, 32 Biomedical and clinical sciences, 42 Health sciences, 52 Psychology, Athlete monitoring, bench press, deadlift, load velocity, squat, smartphone application, strength and conditioning
Source
International Journal of Sports Science and Coaching, ISSN: 1747-9541 (Print); 2048-397X (Online), SAGE Publications. doi: 10.1177/17479541251391967
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© The Author(s) 2025. This article is distributed under the terms of the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).