Footbar Reliability Study: Professional-Level Accuracy Validated by the KNVB

In modern football, performance analysis is no longer reserved for the elite. However, the democratization of football sensors raises a legitimate question among physical trainers and demanding players: what is the real reliability of the measured data?

To answer this question in a scientific and transparent manner, the Footbar R&D team conducted a thorough validation study at the end of 2025 at the campus of the KNVB (the Royal Dutch Football Association). In partnership with Inmotio, a leader in local positioning systems (LPS) for high-level sports, we subjected our algorithm to a battery of rigorous tests.

Here are the detailed results of this evaluation, which places Footbar among the most reliable technologies on the market.

🔬 A methodology based on FIFA protocols

To ensure the objectivity and scientific validity of the results, the test protocol was developed based on the FIFA certification manual for Electronic Performance Tracking Systems (EPTS).

The study involved 8 U23 players. To establish a direct comparison, each participant was simultaneously equipped with:

• The Footbar sensor (placed on the upper back of the calf of the dominant leg).

• The Inmotio LPM reference system (worn on the torso), known for its high spatial precision.

• Synchronized video tracking for manual verification of technical events (shots and passes).

Players performed multi-speed circuits (walking, running, sprinting), 40-meter maximum sprint tests, high-intensity ball possession drills (4v4), and specific shooting tests.

📊 Key results: Precision for performance

The collected data demonstrates the excellence of the Footbar algorithm (end of 2025 version), capable of isolating complex footballer movements with precision rivaling professional equipment.

• 📏 98.5% precision on distance covered in match conditions: During the ball possession exercise (4v4), which perfectly simulates the chaotic conditions and changes of direction of a real match, the average difference in distance measured between the Inmotio reference system and Footbar was only 1.47%. This attests to a precision of over 98.5% on the player's overall movements on the field.

• ⚡️ 96% precision on Maximum Speed (V-Max): Peak speed is a crucial metric for injury prevention and explosiveness analysis. In 40m sprint tests, the Footbar sensor showed great consistency with the Inmotio system, with an average difference of only 3.3% (bias of -0.26 m/s).

• 🎯 93% precision on shot detection (F1-Score): Technical detection is Footbar's signature. During shooting drills, artificial intelligence was able to isolate and classify shots with an F1-score of 0.93 (combining a recall rate of 0.94 and a precision of 0.92). The system perfectly identified specific impacts related to shots, effectively distinguishing them from simple passes.

• The advantage of the accelerometer: Unlike GPS systems which can "drift" and count distance even when you are stationary, Footbar uses an accelerometer which directly detects leg movement. Result: it is often more accurate than professional systems for identifying periods of immobility.

💡 Technological excellence without compromising accessibility

This level of reliability is the result of continuous optimization by our Research & Development team. The improvement of our deep learning models (recurrent neural networks) allows us to translate raw accelerometer signals into high-fidelity actionable statistics.

Today, Footbar's fundamental objective has been achieved: to democratize access to advanced performance analysis in amateur football. We are proud to offer the only technology combining a certified level of reliability against demanding standards, and an affordable price for all players and clubs, amateur and professional alike.

Consult the complete study on SportRxiv: Access the report