Table 1 Definitions of common tracking metrics
Level | Metric | Definition | Common Measures |
|---|---|---|---|
1 | Distance | Cumulative distance | Total, Relative, Distances in speed/acceleration/deceleration zones |
2 | Acceleration (2D) | Instantaneous peak rate of positive change in velocity | Maximal/Peak, Average, Distance/Efforts/Time in acceleration zones |
Deceleration (2D) | Instantaneous peak rate of negative change in velocity | Maximal/Peak, Average, Distance/Efforts/Time in deceleration zones | |
Change of Direction (2D) | Count and intensity of changes of direction derived from positional data | Total, Percentage Difference Left vs Right, Count in intensity zones | |
3 | Accelerometry-derived load | A manufacturer-specific, modified vector magnitude of 3D acceleration values (expressed in AU) | Total, Relative to time, Relative to distance, 2D (excludes vertical axis), 1D (absolute or relative contribution of individual axes) |
Change of Direction (3D) | Count and magnitude (g) of changes of direction derived from inertial sensors | Total, Percentage Left v Right, Count in intensity zones | |
Impacts | A manufacturer-specific metric that provides a count of 3D acceleration values (g) over a threshold | Count and Magnitude of Impacts | |
Collisions/ Tackles | A manufacturer-specific metric that classifies collisions specific to the sport | Count and Magnitude of Collisions | |
Stride Variables | Accelerometry-derived metrics estimating ground contact time | Contact Time, Flying Time, Vertical Stiffness (KN·m) | |
Stride Imbalances | Accelerometry-derived metrics split by left and right side | Percentage Left v Right | |
Hybrid | Speed | Instantaneous peak rate of position change | Maximal/Peak, Average |
Sport-specific Metrics | Specific machine learning algorithms designed to quantifying movement demands per sport | AMF QB throws, Basketball court transition, IH skating strides, Rugby scrum detection, Soccer GK Left v Right Dive Count | |
Metabolic Power | Estimates the energetic demands of high-intensity Level 1 and 2 actions via GPS or LPS data | Metabolic Energy (Cal·kg), Equivalent Distance (distance covered running at constant speed on flat terrain, for a given energy expenditure), Total Metabolic Power (ml·kg·min), Distance/Efforts/Time in Metabolic Power bands |