The aims of the current study were to examine the external validity of inertial based parameters (inertial movement analysis; IMA) to detect multi-planar explosive actions during maximal sprinting, change of direction (COD) and to further determine its reliability, set appropriate magnitude bands for match analysis and assess its variability during international women’s soccer matches. Twenty U20 female soccer players, wearing GPS units with a built-in accelerometer, completed three trials of a 40-m sprint and a 20-m sprint with a change of direction to the right or left at 10-m. Further, thirteen women’s national team players (157 files; 4-27 matches per player) were analyzed to ascertain match-to-match variability. Video synchronization indicated IMA signal was instantaneous with explosive movement (acceleration/deceleration/COD). Peak GPS velocity during the 40-m sprint showed similar reliability (CV = 2.1%) to timing gates, but increased pre- and post-COD (CV = 4.5-13%). IMA variability was greater at the start of sprints (CV = 16-21%) compared to pre- and post-COD (CV = 13-16%). IMA threshold for match analysis was set at 2.5m.s-2 by subtracting one standard deviation from the mean IMA during sprint trials. IMA match variability (CV = 14%) differed from high-speed GPS metrics (35-60%). Practitioners are advised that timing lights should remain the gold standard for monitoring sprint and acceleration capabilities of athletes. However, IMA indicates a reliable method to monitor between match explosive actions and assess changes due to various factors such as congested schedule, tactics, heat or altitude.