Muñoz López, AlejandroMarín Galindo, AlbertoCorral Pérez, JuanCostilla, ManuelSánchez Sixto, AlbertoSañudo Corrales, Francisco de BorjaCasals, CristinaPonce González, Jesús G.2025-01-142025-01-142022Muñoz López, A., Marín Galindo, A., Corral Pérez, J., Costilla, M., Sánchez Sixto, A., Sañudo Corrales, F.d.B.,...,Ponce González, J.G. (2022). Effects of different velocity loss thresholds on passive contractile properties and muscle oxygenation in the squat exercise using free weights. Journal of strength and conditioning, 36 (11), 3056-3064. https://doi.org/0.1519/JSC.0000000000004048.1064-80111533-4287https://hdl.handle.net/11441/166607The current study assessed the impact between different velocity loss thresholds on changes in the muscle contractile properties and muscle oxygenation after a single resistance training session. 30 physically-active men participated in a cross-over study performing three sets of the squat exercise at a lifted speed of ≈ 0.75 m·s -1, with two different velocity loss thresholds: 20% (VL20) vs 40% (VL40) in a randomized order. Contractile properties of the knee extensor muscles were tested using Tensiomyography. In addition, muscle oxygenation was continuously measured from baseline until the end of the exercise session. The Vastus Lateralis showed a significant Moment by Condition interaction in Time Delay (p=0.044), Muscle Displacement (p=0.001), and Contraction Velocity (p=0.007), with greater reductions in VL40. During the execution, the oxygenated haemoglobin and the tissue oxygen index decreased, while the deoxygenated haemoglobin increased (Moment as the main effect, p<0.05), but without a Moment by Condition interaction. In addition, VL40 showed a lower deoxygenation slope in Set 1 (-0.468 %·s-1, p= 0.001) and Set 3 (-0.474 %·s-1, p= 0.037) as well as higher losses in Set 1 (-41.50%, p= 0.003), Set 2 (-41.84%, p= 0.002), and Set 3 (-62.51%, p<0.001). Finally, the recovery slope and increment during the first minute after each set were not significantly different between conditions. In conclusion, using a velocity loss of ≈ 40% resulted in higher neuromuscular impairment and more time under a lower oxygen supply compared to using a velocity loss of ≈ 20% in the squat exercise after a single resistance training session.application/pdf26 p.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/FatigueVelocity-based trainingMuscle recoveryNeuromuscular propertiesStrength traininginfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccesshttps://doi.org/0.1519/JSC.0000000000004048