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Metric VBT validation & accuracy

We compared Metric's vision tracking system against a GymAware tether unit (the $1,995 linear-position transducer) across 95 repetitions in 15 sets, looking at mean and peak velocity on bench press, deadlift, squat and cleans. We tested multiple Metric recording setups, including 45° angles, low-angles, 30fps footage, 720p, 4K, low-light and glare environments. Here's how Metric (iOS v6.9 and Android v1.2) compares.

CCC 0.982 MEAN VELOCITY CONCORDANCE vs GymAware · 95 reps · bench, deadlift, squat, cleans · systematic bias +0.02 m/s
CCC 0.975 PEAK VELOCITY CONCORDANCE vs GymAware · 95 reps · bench, deadlift, squat, cleans · systematic bias −0.05 m/s
100% REP DETECTION Across all camera setups and lighting conditions tested — 45°, floor-level, low-light, glare, clutter

Rep-by-rep mean velocity agreement

Lin's concordance correlation coefficient (CCC) measures not just linear association but also systematic bias and scale differences — it's more rigorous than Pearson r for method-comparison studies. 0.9+ is considered excellent agreement; values above 0.98 approach the limit of what two instruments measuring the same physical quantity can achieve.

00.511.52 0.511.52 GymAware mean velocity (m/s) Metric mean velocity (m/s) CCC = 0.982
SOURCE · Internal validation June 2026 · Metric iOS v6.9 / Android v1.2 · 95 reps, 15 sets · bench press, deadlift, squat, cleans

Rep-by-rep peak velocity agreement

Peak velocity is harder to measure accurately than mean velocity, susceptible to frame-rate and smoothing artefacts. The CCC of 0.975 across 95 reps (bench, deadlift, squat and cleans, including explosive clean peaks above 2.5 m/s) includes videos recorded at both 60fps and 30fps across Android and iOS devices.

0.00.51.01.52.02.53.0 0.51.01.52.02.53.0 GymAware peak velocity (m/s) Metric peak velocity (m/s) CCC = 0.975
SOURCE · Internal validation June 2026 · Metric iOS v6.9 / Android v1.2 · 95 reps, 15 sets · bench press, deadlift, squat, cleans

Mean absolute error vs GymAware

MAE is the average magnitude of the per-rep difference. How far off each device is for the same repetition in metres per second. Compared to GymAware, Metric reads slightly faster on mean velocity and slightly lower on peak velocity.

Mean velocity +0.044 m/s
Peak velocity −0.088 m/s
MEAN ABSOLUTE ERROR · Sign indicates direction of systematic bias · Scale ±0.40 m/s

More in-house validation

Additional in-house and user-contributed studies covering different reference devices, lift types, and training contexts — alongside the GymAware comparison above.

Don't take our word for it. Metric is also externally validated.

Five peer-reviewed papers from separate research groups tested Metric against lab-grade hardware — 3D motion capture systems and linear-position transducers. We offered recording guidance and data export support but had no input in the published results or analysis.

Use Metric in your research

Running a study and want to use Metric as a measurement tool? Get in touch. Our engineering team is available for technical questions and can help with data export.

Research with Metric
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