Rapid Directional Change Degrades GPS Distance Measurement Validity during Intermittent Intensity Running

• DOI: 10.1371/journal.pone.0093693
• Publication Date: 2014-04-14T16:28:14Z
• Authors: Jonathan C. Rawstorn; Ralph Maddison; Ajmol Ali; Andrew Foskett; Nicholas Gant
• Keywords: Team sport

Use of the Global Positioning System (GPS) for quantifying athletic performance is common in many team sports. The effect running velocity on measurement validity well established, but influence rapid directional change not understood sport applications. This was systematically evaluated using multidirectional and curvilinear adaptations a validated soccer simulation protocol that maintained identical profiles. Team athletes completed 90 min trials Loughborough Intermittent Shuttle-running Test movement pattern curvilinear, shuttle tracks while wearing 5 Hz (with interpolated 15 output) GPS device. Reference total distance (13 200 m) over- underestimated during (2.61±0.80%) (−3.17±2.46%) trials, respectively. Within-epoch uncertainty dispersion widest trial, particularly jog run phases. Relative reliability excellent both (Curvilinear r = 1.00, slope 1.03, ICC 1.00; Shuttle 0.99, 0.97, 0.99). Absolute superior trial SEM 0 m, CV 2.16%, LOA ± 223 m; 119 2.44%, 453 m). Rapid degrades accuracy absolute measurement, caution recommended when to quantify patterns.