Acute Responses to Traditional and Cluster-Set Squat Training With and Without Blood Flow Restriction

Abstract

Cornejo-Daza, PJ, Sánchez-Valdepeñas, J, Páez-Maldonado, J, Rodiles-Guerrero, L, Boullosa, D, León-Prados, JA, Wernbom, M, and Pareja-Blanco, F. Acute responses to traditional and cluster-set squat training with and without blood flow restriction. J Strength Cond Res 38(8): 1401-1412, 2024-To compare the acute responses to different set configurations (cluster [CLU] vs. traditional [TRA]) under distinct blood flow conditions (free vs. restricted) in full-squat (SQ). Twenty resistance-trained males performed 4 protocols that differed in the set configuration (TRA: continuous repetitions; vs. CLU: 30 seconds of rest every 2 repetitions) and in the blood flow condition (FF: free-flow; vs. blood flow restriction [BFR]: 50% of arterial occlusion pressure). The relative intensity (60% 1RM), volume (3 sets of 8 repetitions), and resting time (2 minutes) were equated. Mean propulsive force (MPF), velocity (MPV) and power (MPP), and electromyography (EMG) parameters were recorded during each repetition. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ) height, maximal voluntary isometric contraction, in SQ, and movement velocity against the load that elicited a 1 m·s -1 velocity at baseline (V1-load) in SQ were assessed at pre- and post-exercise. The CLU protocols allowed a better maintenance of MPF, MPV, MPP, and EMG median frequency during the exercise compared to TRA (clu-time interaction, p < 0.05). The TRA protocols experienced greater impairments post-exercise in TMG- and EMG-derived variables (clu-time interaction, p < 0.05) and SQ and CMJ performance (clu-time interaction, p = 0.08 and p < 0.05, respectively), as well as higher blood lactate concentrations (clu-time interaction, p < 0.001) than CLU. Moreover, BFR displayed decreases in TMG variables (bfr-time interaction, p < 0.01), but BFR-CLU resulted in the greatest reduction in twitch contraction time ( p < 0.001). Cluster sets reduced fatigue during and after the training session and BFR exacerbated impairments in muscle mechanical properties; however, the combination of both could improve contraction speed after exercise.

Figure 1.

Schematic representation of the different resistance exercise protocols and the battery of tests performed before and after each resistance exercise protocol and the timeline. FF-TRA: protocol consisting of performing 3 sets of 8 repetitions with 60% 1RM with free blood flow; BFR-TRA: protocol consisting of performing 3 sets of 8 repetitions with 60% 1RM with blood flow restriction; FF-CLU: protocol consisting of performing 3 sets of 8 repetitions with 30-s rests every 2 repetitions with 60% 1RM with free blood flow; BFR-CLU: protocol consisting of performing 3 sets of 8 repetitions with 30-s rests every 2 repetitions with 60% 1RM with blood flow restriction; TMG = tensiomyography; La+ = blood lactate; CMJ = countermovement jump; MVIC = maximal voluntary isometric contraction; V1-load = load that elicited a 1 m·s⁻¹ velocity at the baseline measure; PRE = before the protocol; POST = after the protocol.

Figure 2.

Evolution of mechanical performance throughout the 24 repetitions for the 4 protocols. A) Mean propulsive force; B) mean propulsive velocity; and C) mean propulsive power. Data are mean ± SD, n = 20. FF-TRA: protocol consisting of performing 3 sets of 8 repetitions with 60% 1RM with free blood flow; BFR-TRA: protocol consisting of performing 3 sets of 8 repetitions with 60% 1RM with blood flow restriction; FF-CLU: protocol consisting of performing 3 sets of 8 repetitions with 30-s rests every 2 repetitions with 60% 1RM with free blood flow; BFR-CLU: protocol consisting of performing 3 sets of 8 repetitions with 30-s rests every 2 repetitions with 60% 1RM with blood flow restriction. Within-protocol significant differences regarding the first repetition of each set: *p < 0.05.

Figure 3.

Evolution of neuromuscular parameters throughout the 24 repetitions for 4 protocols. A) Relative root mean square averaged from the vastus medialis (VME) and vastus lateralis (VLA) muscles; and B) relative median frequency averaged from the VME and VLA muscles. Data are mean ± SD, n = 20. FF-TRA: protocol consisting of performing 3 sets of 8 repetitions with 60% 1RM with free blood flow; BFR-TRA: protocol consisting of performing 3 sets of 8 repetitions with 60% 1RM with blood flow restriction; FF-CLU: protocol consisting of performing 3 sets of 8 repetitions with 30-s rests every 2 repetitions with 60% 1RM with free blood flow; BFR-CLU: protocol consisting of performing 3 sets of 8 repetitions with 30-s rests every 2 repetitions with 60% 1RM with blood flow restriction. Within-protocol significant differences regarding the first repetition of each set: *p < 0.05.