Martínez-Rodríguez, José AntonioCrotin, Ryan LNeville, JonathonBarcelo, Roderick ACronin, John B2026-03-092026-03-092026-02-25Applied Sciences, ISSN: 2076-3417 (Print); 2076-3417 (Online), MDPI AG, 16(5), 2224-2224. doi: 10.3390/app160522242076-34172076-3417http://hdl.handle.net/10292/20737<jats:p>The purpose of this study was to quantify the between-session reliability of time, velocity, and distance measures over 54.7 m straight-line and home-to-second base sprints (curvilinear), using global positioning satellite (GPS) technology. Twelve trained male high school baseball position players attended four sessions: one familiarization session and three identical testing sessions, separated by at least two days, each consisting of two linear and two curvilinear trials. There was no statistically significant evidence (p &lt; 0.05) of systematic change in any of the variables between sessions, with the majority of the mean percent changes ranging from −2.7 to 2.5%, and only four between-session comparisons greater than 2% (−6.2 to 3.4%). In terms of absolute consistency, no measure exceeded a coefficient of variation (CV) of 10%, with the majority (93%) of the CVs under 5%. With regard to relative consistency, 66% of the measures had intraclass correlation coefficients (ICCs) greater than 0.74, ranging from 0.76 to 0.98. Comparison of smallest worthwhile change (SWC) values with CV-derived typical error indicated that several key time- and speed-based metrics were sensitive to meaningful performance changes, with error estimates that were comparable to or smaller than SWC. In contrast, event-timed typical errors (e.g., time to peak speed) were substantially greater than the SWC, indicating limited sensitivity for detecting small performance changes. The non-significant changes in the mean, low CVs, and high ICCs, for the most part, over repeated testing occasions, indicate acceptable between-session reliability for many of the procedures and GPS-derived variables examined in this study. Practitioners should prioritize linear time at 41.1 m and 54.7 m and velocity at 27.4 m and 41.1 m for return-to-play and short-term performance tracking. For curvilinear running, peak speed before first base, peak speed before second base and after first base, and speed at 41.1 m are the most suitable monitoring metrics based on the results. Specifically, speed at 41.1 m should be considered for return-to-play and short-term performance tracking, while peak speed before first base and peak speed before second base and after first base may be used cautiously when larger performance changes are expected.</jats:p>© 2026 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.32 Biomedical and Clinical Sciences3202 Clinical Sciences42 Health SciencesClinical Researchvelocity-time-distance measureshigh schoolbaseballJournal ArticleOpenAccess10.3390/app16052224