Validation of a Single-Session Protocol to Determine the Load-Velocity Profile and One-Repetition Maximum for the Back Squat Exercise

Gomes, M, Fitas, A, Santos, P, Pezarat-Correia, P, and Mendonca, GV. Validation of a single session protocol to determine the load-velocity profile and one-repetition maximum for the back squat exercise. J Strength Cond Res 38(6): 1013-1018, 2024-We investigated whether a single session of absolute incremental loading is valid to obtain the individual load-velocity profile (LVP) and 1 repetition maximum (1RM) for the free-weight parallel back squat. Twenty strength-trained male subjects completed 3 testing sessions, including a baseline 1RM session and 2 LVP sessions (LVPrel based on incremental relative loads and LVPabs based on absolute load increments until 1RM). The 1RM load was compared between the baseline and LVPabs. The load at zero velocity (load-axis intercept [L0]), maximal velocity capacity (velocity-axis intercept [V0]), slope, and area under the load-velocity relationship line (Aline) were compared between the LVPrel and LVPabs using equivalence testing through 2 one-sided t-tests. Measurement accuracy was calculated using the absolute percent error. The 1RM measured at baseline and LVPabs was equivalent and presented a low absolute percent error (1.2%). The following LVP parameters were equivalent between LVPrel and LVPabs: 1RM, L0, and Aline because the mean difference between sessions was close to zero and the Bland-Altman limits of agreement (1RM:5.3 kg; L0:6.8 kg; Aline: 9.5 kg<middle dot>m-1<middle dot>s-1) were contained within the a priori defined +/- equivalent margins (5% for 1RM and L0 and 10% for Aline). The aforementioned variables presented a low absolute percent error. However, slope and V0 were not equivalent between sessions. In conclusion, a single session of absolute incremental loading is a valid approach to obtain the L0 and Aline of the individual LVP and 1RM, and can be used to efficiently track the magnitude of neuromuscular adaptations throughout the training cycles for the free-weight back squat.