Inter-test reliability in 1RM and barbell velocity during submaximal and maximal tests in the back squat : A study on elite Swedish Power- and Olympic weightlifters

Purpose: This study aimed to investigate the inter-test reliability of mean velocity (MV) at various loads, ranging from submaximal to maximal, and one-repetition maximum (1RM) for weight (KG) in the free-weight back squat among an elite population of weightlifters and powerlifters Method: Six male and five female elite athletes specializing in Olympic weightlifting and powerlifting participated in the study. Data collection consisted of two sessions separated by a minimum of 72 hours. During the 1RM sessions, participants completed a load-velocity profile (LVP), during which mean velocity (MV) was measured at different loads (30-100% of 1RM). Inter-test reliability was evaluated using Bland-Altman analysis, coefficients of variation (CV), and Pearson's r. MV was measured using a linear encoder (Model 220, Madrid, Spain) attached to the barbell. Results: The Bland-Altman analysis revealed no systematic differences in mean velocity (MV) at submaximal loads 40% up to 90% of 1RM (0.05 ± 0.02 m/s, CV: 4.82%). However, variations in 30% of 1RM (CV: 6.83%) and MV at 1RM loads (V1RM) were observed (CV: 16.47%). Pearson´s correlation coefficient showed a practically perfect relationship between the 1RM tests (r² = 0.9953) exhibiting excellent reliability (CV: 1.22%) measuring differences in absolute weight. The strength assessment showed a higher subject relative strength ratio (RSR) (2.28 ± 0.16 kg·bm⁻¹ and 2.12 ± 0.30 kg·bm⁻¹, respectively) compared to test subjects used in previous studies. Conclusion: Our findings indicate that, for elite powerlifters and weightlifters, mean velocity (MV) between 40% and 90% of 1RM displays high levels of reliability between sessions, while test retest-reliability for 1RM (KG) values was high. The less precise MV measurements observed at loads outside this range suggest potential limitations for velocity-based training at very low or maximal intensities. This observation has important implications for velocity-based training approaches, emphasizing the use of individualized velocity-load profiles to ensure appropriate training stimuli across the loading spectrum.