Scopri l'ottimizzazione definitiva del monitoraggio della velocità

We’ve optimised our algorithms to match the speed of any leading VBT device. Now, velocity feedback is provided immediately after you complete each rep.

SCARICA ORA L'APP SPLEEFT PER iOS, ANDROID E APPLE WATCH!

Activate Boost Mode Now

By default, Boost Mode is enabled on both the Apple Watch and the iPhone. If it’s not active, you can enable it in the Spleeft settings on your Apple Watch. For iPhone-based measurements, go to Settings > Real-time Feedback Settings.

Once enabled, you’ll notice significantly faster feedback after each repetition. However, to ensure measurement reliability, you should remain still momentarily to allow for zero-point calibration, just as before. On the Apple Watch, you’ll feel a vibration once calibration is complete. On the iPhone, you’ll see a visual cue: a message changing from green to orange. Additionally, ensure your iPhone’s volume is turned on—Spleeft will say “Go!” to signal that calibration has finished, and you’re ready for the next rep.

The stationary phase detection algorithm used for calibration has also been optimised for maximum speed.

No Time to Wait? No Problem

While taking short rests between reps is beneficial for performance, we understand some training contexts don’t allow it. Spleeft continuously checks each detected stationary phase to ensure all previous reps are recorded and validated. If you skip the calibration pause, an accumulated error may occur. In such cases, Spleeft will prioritize and store the most reliable data available.

If you experience any issues with the new mode, you can always switch back to the Balanced Mode, which uses the previous algorithm. As always, we value user feedback to continue improving.

Additional Enhancements

We’ve introduced further optimizations tailored to specific exercise types, including machine-based movements such as lat pull downs and leg extensions. As you may know, placing the iPhone on the vertically moving weight stack allows you to measure velocity for nearly any exercise. We’re also continuing to improve support for Olympic lifts.

Thanks to your feedback, we’ve implemented additional enhancements in the new Coach Mode.

What Was the Challenge?

Until now, our algorithms were already nearly as accurate as one of the most validated VBT devices available. Velocity measurements obtained via Apple Watch have already undergone independent validation, and a new study further confirming our data is coming soon.

However, to ensure precision, the user had to remain completely still between reps for signal calibration. This yielded highly reliable results, but in practice—especially in the gym—barbell vibrations or continuous reps often delayed feedback and compromised the user experience.

With the new update, we’ve preserved that accuracy while now providing velocity feedback immediately after the concentric phase. As a result, Spleeft offers a much more seamless and efficient gym experience.

Understanding Accelerometer Limitations—and Our Solution

Below is a graph illustrating several squat reps. After the first rep, there’s a long pause used for signal calibration. Then, three consecutive reps are performed without pausing. As seen in the graph, an error—known as drift—gradually accumulates when there’s no reference point like a stationary phase. This drift mainly results from the inherent errors in mathematical integration and sensor orientation changes.

However, our latest research (conducted just prior to this update) shows that for a single rep, this drift isn’t significant enough to affect the reliability of the average velocity. In fact, removing the recalibration requirement eliminates one of the main sources of error: bar vibrations caused by explosive movements.

Thus, the most reliable method remains performing one rep followed by a brief pause for recalibration to prevent error accumulation. The advantage now is that velocity data is available immediately, giving you time to interpret and process it—whether it met expectations, if there was velocity loss, etc.—even as the system calibrates in the background.

We’ll soon publish a more detailed article explaining the research behind this update. Additionally, our latest findings will be applied to altezza del salto measurements—covering CMJ, SJ, DJ, and precision mode.