Author(s): DELLO STRITTO, E., ROMAGNOLI, R., QUAGLIAROTTI, C., PIACENTINI, M.F., Institution: UNIVERSITY OF ROME , Country: ITALY, Abstract-ID: 2280

INTRODUCTION:
Velocity-based training is an objective method of autoregulation that uses barbell velocity and velocity loss to manage and quantify resistance training (RT) sessions. However, in large team settings, electronic devices are not always available for all athletes. For this reason, the perception of barbell velocity (VP) has recently gained interest, with studies demonstrating that after a period of familiarization1,2, VP improves to practically match real velocity (VR). What is still unexplored is how fatigue affects the accuracy of VP. The aim of the present study was to investigate the effects of mental (MF) and physical fatigue (PF) on VP and perception of velocity loss (VLP).
METHODS:
Eleven subjects (23.16±2.12years; RT experience: 4.5±2.31 years) participated in a seven-session experimental protocol. The first four sessions aimed to familiarize subjects with VP and VLP. The last three sessions were performed in a PF, MF or control condition in a randomized order. The accuracy in perceiving concentric velocity before and after the different conditions was assessed during a test with 2 blinded-loads (heavy: ?80%1RM, medium: ? 60%1RM), in the Back Squat exercise. PF was induced by 5 x back squats at 75%1RM until exhaustion, while MF was induced by a 45-minute AX-CPT test. The control session involved watching a 45-minute unemotional documentary. VP, VLP, and physical performance assessed by a countermovement jump (CMJ), rate of force development (RFD), and maximum voluntary contraction (MVC) were measured before and after each condition. Data were analysed with a Paired t-test to compare pre- and post-fatigue protocol measurements, the level of significance applied was p<0.05.

RESULTS:
VP and VLP were unaffected (p>0.05) by the fatiguing protocols despite a significant reduction in VR (VRrest:0.67±0.08 m·s-1; VR PF:0.44±0.10 m·s-1; VRMF:0.51±0.13 m·s-1). Performance decreased significantly (p<0.05) after PF and MF (CMJ: -19%, -7%; RFDmax: -25%, -9%; RFD0-100ms: -22%, -9%; RFD0-200ms: -19%, -10%; MVC: -20%, -10%) Moreover, VAS reported an increase in perceived MF after AX-CPT but not after the documentary. No differences were seen in the control condition (p>0.05).
CONCLUSION:
Despite a significant reduction in VR, both fatiguing protocols did not alter VP during back squat. These data confirm previous studies performed with shorter protocols3 confirming that VP is a stable parameter on which practitioners can base their training despite different levels of fatigue. Furthermore, CMJ, RFD, and MVC performance were negatively affected by both conditions. While this it is well-established under PF conditions, further investigation is needed to better understand the effects of MF.

References:
1. Dello Iacono, A., et al., (2023
2. Romagnoli, R., et al., (2022)
3 Romagnoli, R., et al., (2022a)