Author(s): GRAMAZIO, A., DELLO STRITTO, E., ROMAGNOLI, R., PIACENTINI, M.F., Institution: UNIVERSITY OF ROME , Country: ITALY, Abstract-ID: 858

INTRODUCTION:
Velocity Perception (PV) refers to the ability to perceive barbell movement velocity during resistance training exercises and has recently emerged as a low-cost alternative to monitoring devices for prescribing velocity-based training (VBT) sessions (1). Although several studies have reported promising findings, PV application remains limited by insufficient accuracy and marked interindividual variability, which currently prevents its reliable use for VBT sessions prescription (1). Thus, the present study aimed to investigate the effect of error-based feedback on PV, hypothesizing improved accuracy and decreased interindividual variability.
METHODS:
Twenty-one resistance-trained participants completed five back squat sessions. The first three sessions were dedicated to PV familiarization through the combined use of an Encoder (Vitruve) and a validated PV scale (1). During the fourth (S4) and fifth sessions (S5), participants performed PV tests consisting of five sets (three moderate and two heavy loads) with concealed loads. Participants reported the perceived velocity (Vp) of the first repetition of each set. PV accuracy was quantified using the absolute delta score (|DS|), defined as the absolute difference between Vp and the recorded real velocity (Vr) (|DS| = |Vp - Vr|). At the end of S4, participants received feedback regarding the magnitude and direction (overestimation or underestimation) of the PV error; during S5 the effect of error-based feedback was evaluated. Participants were then divided in Precise (|DS| at S4<0.08 m*s-1; N=11) and Imprecise (|DS| at S4>=0.08 m*s-1; N=10) based on a previously suggested cut-off of |DS|=0.08 m*s-1 (1), to investigate potential differential effects of feedback. An aligned rank transform ANOVA was performed with group (between-subjects) and time (within-subjects) factors.
RESULTS:
A significant group × time interaction was observed for PV accuracy (F(1,19) =9.35, p=0.006, partial eta squared =0.33). While Precise individuals showed no meaningful changes in |DS| between sessions (pre median=0.05 m*s-1; post median=0.06 m*s-1), Imprecise individuals exhibited a significant reduction in PV error following error-based feedback (pre median=0.10 m*s-1; post median=0.07 m*s-1; V = 43, Z=-2.36, p=0.018, r=0.75). As a result, between-group differences observed before feedback (p<0.01) were no longer present after (p=0.45).
CONCLUSION:
Error-based feedback selectively improves velocity perception in individuals with low initial accuracy, thus reducing interindividual variability. These findings suggest that targeted feedback may represent a practical strategy to enhance PV accuracy and support its application for prescribing training intensity in VBT when monitoring devices are unavailable or scarce.

REFERENCES:
1. Dello Stritto E, et al. 2025.