Amdi, CHCleather, DJTallent, J2026-05-282026-05-282025-09-08International Journal of Sports Science and Coaching, ISSN: 1747-9541 (Print); 2048-397X (Online), SAGE Publications, 21(2), 1055-1065. doi: 10.1177/174795412513713081747-95412048-397Xhttp://hdl.handle.net/10292/21285Research suggests that biological sex and strength level influence the load-velocity profile. However, existing research have not appropriately statistically accounted for the interdependencies between sex and relative strength. This exploratory study investigated load-velocity profiles of 24 resistance-trained participants (14 males, 10 females; back squat 1.69 × and 1.28 × body mass, respectively) using mixed-effects modelling to account for relative strength and individual variability. Participants completed 2–3 incremental back squat loading tests (20 kg to one-repetition maximum [1RM]). 1RM assessments showed excellent reliability, while mean concentric velocity (MCV) at 0–40% of 1RM demonstrated good-to-excellent reliability, with reliability systematically declining at higher relative loads. Small effects of biological sex on load-velocity profiles was found at 0–40% of 1RM (0.07–0.13 m/s, BF = 10.702–47.682, pd = 91–98%), while the effects of relative strength were more pronounced at 0–70% of 1RM (0.18–0.44 m/s, BF = 26.972–2399.000, pd = 96–100%), both with diminishing differences as relative load increased. These findings challenge assumptions about sex as a major load-velocity profile moderator when accounting for relative strength and individual variability. While exploratory and requiring replication, the study recommends future research employ more nuanced statistical methods, recruit homogeneously trained samples, and minimise measurement noise to avoid potential type-I errors.© The Author(s) 2025. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).https://creativecommons.org/licenses/by-nc/4.0/42 Health Sciences4207 Sports Science and Exercise11 Medical and Health Sciences17 Psychology and Cognitive Sciences32 Biomedical and clinical sciences42 Health sciences52 PsychologyBody compositiongenderresistance trainingsmartphone-based wearable deviceJournal ArticleOpenAccess10.1177/17479541251371308