Accelerations: Are You Actually Measuring Performance, or Just Guessing?

In the world of high-performance sports, data is king. Coaches, analysts, and sports scientists rely on GPS and tracking systems to make critical decisions about player load, injury prevention, and tactical preparation. Among the most popular metrics? Accelerations.

But here is a provocative question for the analysts reading this: Do you actually know what your system is measuring?

A recent, insightful piece from Valerio Roberti highlights a growing concern in the industry: the “Black Box” problem of sports tracking technology.

The Comparison Conundrum

We’ve all seen it. A team decides to switch tracking systems or compare their current data against a new provider. The expectation is simple: “I want to see the same number of accelerations.”

Yet, time and time again, the numbers don’t match. And when engineers try to reconcile those differences, they hit a wall. Even when using the same thresholds—say, 2.5 m/s²—the counts remain inconsistent.

Why? Because the way “acceleration” is defined behind the scenes is often shielded from the user.

Inside the Black Box

The article points out that while we obsess over the output, we rarely interrogate the input. To truly understand your data, you need to know the answers to these fundamental questions:

  • Thresholds: Is the system identifying an acceleration at 2.5 m/s²?
  • Duration: Is there a time filter (e.g., must stay above the threshold for 0.5 seconds)?
  • Filtering: What noise-reduction filters are applied to the speed data before the calculation is even made?
  • Reproducibility: Can you export the raw, instantaneous data and manually verify the calculation?

If you cannot answer these questions, you are relying on a proprietary algorithm—a “Black Box”—that dictates your training decisions without you fully understanding the logic.

Scientific Transparency: The Gold Standard

In science, a metric is only as good as its reproducibility. If two researchers take the same dataset and apply the same rules, they should get the same result. When tracking companies hide their calculation methods, they aren’t just protecting “intellectual property”; they are potentially obscuring the validity of your performance insights.

As the article argues: Transparency doesn’t limit innovation; it makes it credible.

The “Truth Test” for Your Data

If you want to know if your current tracking system is reliable, put it to the test:

  1. Can you pinpoint the exact moment an acceleration event was detected?
  2. Have you ever compared your data against match video?
  3. If you manually count accelerations from video, does the system match your count?

If the answer to these is “no,” you might be measuring noise rather than performance.

Moving Beyond the “Count”

The final, and perhaps most important, takeaway is that maybe—just maybe—we are focusing on the wrong thing. Are “counts” of accelerations truly the most representative way to look at athletic performance?

Maybe it’s time to move away from simply counting events and start looking at the mechanical intensity of “bursts.”

The industry is evolving, and it’s time for performance staff to stop being passive consumers of data and start demanding total transparency. After all, if you don’t know exactly what you’re measuring, you can’t be sure you’re improving it.

Check out the original article at gpexe.com for a deeper dive into the technical side of mechanical analysis and additional articles.

This summary was generated with the assistance of Gemini based on the original article, with the aim of translating the research into insights for coaches and support staff.

Niels de Vries
Niels de Vries
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