Temporal Stability and Practical Applicability of Velocity and Velocity-Loss Perception in Back Squat over Eight Weeks.

Background: Subjective autoregulation methods are gaining interest among resistance-trained athletes. In particular, velocity perception (PV) and velocity loss perception (PVL) have shown promising practical applicability. This study aimed to investigate the temporal stability of PV and PVL across an eight-week period. Methods: Fifteen participants, after sessions of familiarization with PV and PVL, completed three test sessions: the first 48 h after the familiarization, and the others 4 and 8 weeks later. Each test session included five sets of back squats with light (55%-60%-65% 1RM) and heavy (75%-85% 1RM) loads. Light loads were executed with a 10-20-30%VL, while heavy loads with a 10-20%VL. PV accuracy was assessed using the |DeltaScore|, defined as the absolute difference between perceived velocity (Vp) and the velocity provided by the encoder (Vr): |DeltaScore| = |Vp - Vr|. PVL was measured by the |Vscore|, defined as the absolute difference between the number of repetitions perceived as correct relative to the target %VL (Np) and the repetitions that actually met it (Nr): |Vscore| = |Np - Nr|. Results: The results demonstrated that both PV and PVL are stable after 4 weeks at all loads and %VL (p > 0.05). In contrast, after 8 weeks, PV accuracy significantly decreased at all loads (p < 0.05; η2p = 0.04), whereas PVL accuracy decreased only at light loads (p < 0.05; η2p = 0.18). Moreover, PV error values remained below the previously suggested acceptability threshold of 0.09 m·s-1 for up to 4 weeks. This error threshold corresponds to a load variation of ~10% 1RM in the back squat. Conclusions: The present results support the applicability of PV and PVL in real training contexts for a maximum of 4 weeks when monitoring devices are unavailable.