Apple Watch.
5 articles.

Apple Watch 1.5-Mile Test: Hands-Free VO2 Max
Run the 1.5-mile VO2 max test hands-free on your Apple Watch: no stopwatch, no track math, just one number out. Here is the protocol I trust the most.
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Apple Watch Yoyo Test: Hands-Free VO2 Max
Run the Yoyo intermittent recovery test on your Apple Watch with haptic cues. Hands-free protocol for soccer, basketball, and team-sport athletes.
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Apple Watch Balke Test: Hands-Free VO2 Max
How to run the 15-minute Balke test on your Apple Watch. Hands-free pacing, no track measurement, plus the regression that turns distance into VO2 max.
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iPhone vs Apple Watch for the Beep Test
iPhone vs Apple Watch for the beep test: same Léger 1988 audio, same regression, same accuracy. The choice is wrist haptic vs screen glance, with the studies.
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Apple Watch Beep Test: Hands-Free VO2 Max
How to run the 20-meter beep test on your Apple Watch with haptic cues. Setup, pacing, level reading, and the fixes for outdoor noise issues that I trust most.
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