Validity and Reliability of GPS for Measuring Distance Travelled in Field-Based Team Sports

Gray A.J., Jenkins D., Andrews M.H., Taaffe D.R., Glover M.L.

Objective:
The study aimed to investigate the impact of movement intensity and path linearity on the validity and reliability of global positioning system (GPS) distance measurements.

Methods:

One participant wore eight 1-Hz GPS receivers while performing walking, jogging, running, and sprinting activities over both linear and non-linear 200-m courses.
Five trials were conducted at each intensity level on each course.
Data from seven GPS receivers were analyzed after excluding one receiver with data collection errors.
Mean and percent bias of GPS distance values were calculated for each activity and course type.
Statistical analysis compared GPS distance values between different activities and courses.
Coefficient of variation within and between receivers was calculated to assess reliability.
Results:

On the linear 200-m course, GPS distance values were 205.8 ± 2.4 m (2.8%), 201.8 ± 2.8 m (0.8%), 203.1 ± 2.2 m (1.5%), and 205.2 ± 4 m (2.5%) for walking, jogging, running, and sprinting, respectively.
Significant differences were found between walking/sprinting distances and jogging/running distances (p < 0.05). On the non-linear 200-m course, GPS distance values were 198.9 ± 3.5 m (70.5%), 188.3 ± 2 m (75.8%), 184.6 ± 2.9 m (77.7%), and 180.4 ± 5.7 m (79.8%) for walking, jogging, running, and sprinting, respectively. Distances on the non-linear course were significantly lower than those on the linear course for all activities (p < 0.05). Differences between all non-linear movement intensities were significant (p < 0.05). The overall coefficient of variation within and between receivers was 2.6% and 2.8%, respectively. Conclusion: Path linearity and movement intensity influence GPS distance accuracy due to inherent positioning errors, update rate, and usage conditions. Reliability decreases with higher movement intensity.

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