Acute Responses to Different Velocity Loss Thresholds during Squat Exercise with Blood-Flow Restriction in Strength-Trained Men

• Published in: Sports (Basel) Vol. 12; no. 6; p. 171
• Main Authors: Sánchez-Valdepeñas, Juan, Cornejo-Daza, Pedro J, Rodiles-Guerrero, Luis, Páez-Maldonado, Jose A, Sánchez-Moreno, Miguel, Bachero-Mena, Beatriz, Saez de Villarreal, Eduardo, Pareja-Blanco, Fernando
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20-06-2024; MDPI
• Subjects: Acute effects; Blood pressure; Electromyography; Exercise; fatigue; Lactic acid; Mechanical properties; Metabolic response; Metabolism; Muscle contraction; Muscles; neuromuscular; resistance training; tensiomyography; Velocity; Germany; Spain; fatigue; metabolic response; neuromuscular; resistance training; tensiomyography
• ISSN: 2075-4663; 2075-4663
• DOI: 10.3390/sports12060171

(1) Background: The aim of this paper is to analyze the acute effects of different velocity loss (VL) thresholds during a full squat (SQ) with blood-flow restriction (BFR) on strength performance, neuromuscular activity, metabolic response, and muscle contractile properties. (2) Methods: Twenty strength-trained men performed four protocols that differed in the VL achieved within the set (BFR0: 0% VL; BFR10: 10% VL; BFR20: 20% VL; and BFR40: 40% VL). The relative intensity (60% 1RM), recovery between sets (2 min), number of sets (3), and level of BFR (50% of arterial occlusion pressure) were matched between protocols. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ), maximal voluntary isometric SQ contraction (MVIC), and performance with the absolute load required to achieve 1 m·s
at baseline measurements in SQ were assessed before and after the protocols. (3) Results: BFR40 resulted in higher EMG alterations during and after exercise than the other protocols (
< 0.05). BFR40 also induced greater impairments in TMG-derived variables and BFR10 decreased contraction time. Higher blood lactate concentrations were found as the VL within the set increased. BFR0 and BFR10 showed significantly increased median frequencies in post-exercise MVIC. (4) Conclusions: High VL thresholds (BFR40) accentuated metabolic and neuromuscular stress, and produced increased alterations in muscles' mechanical properties. Low VL could potentiate post-exercise neuromuscular activity and muscle contractile properties.