Enhanced Reaction Time Measurement System Based on 3D Accelerometer in Athletics

Area of Science:

• Biomechanics
• Sports Science
• Wearable Technology

Background:

• Reaction time (RT) is crucial for neuromuscular and cognitive performance.
• Existing RT measurement methods often lack portability or focus on localized movements, limiting whole-body assessment.
• There is a need for reliable, portable systems to measure RT in dynamic, whole-body activities like sprint starts.

Purpose of the Study:

• To develop and validate a portable inertial measurement unit (IMU)-based system for measuring reaction time during sprint starts.
• To enable real-time, accurate assessment of whole-body movement onset in sports and research environments.

Main Methods:

• A portable IMU system integrating an accelerometer and microcontroller was developed.
• The system generates auditory stimuli, acquires acceleration data at 1 kHz, and computes movement onset using a calibrated acceleration threshold.
• Desktop and smartphone applications were created for system control, feedback, and data storage.

Main Results:

• The IMU system demonstrated good agreement with high-speed camera measurements (R² = 0.9391).
• Mean bias was -1.35 ms, with 95% limits of agreement within ±25 ms.
• The system achieved high temporal resolution and real-time movement onset detection.

Conclusions:

• The proposed IMU-based system provides a portable, reliable, and accurate method for assessing whole-body reaction time during sprint starts.
• This technology facilitates straightforward deployment for realistic sports and research applications.
• The system enhances the ability to evaluate neuromuscular and cognitive performance in dynamic contexts.