Velocity Drives Greater Power Observed During Back Squat Using Cluster Sets

Abstract

This investigation compared the kinetics and kinematics of cluster sets (CLU) and traditional sets (TRD) during back squat in trained (RT) and untrained (UT) men. Twenty-four participants (RT = 12, 25 ± 1 year, 179.1 ± 2.2 cm, 84.6 ± 2.1 kg; UT = 12, 25 ± 1 year, 180.1 ± 1.8 cm, 85.4 ± 3.8 kg) performed TRD (4 × 10, 120-second rest) and CLU (4 × (2 × 5) 30 seconds between clusters; 90 seconds between sets) with 70% one repetition maximum, randomly. Kinematics and kinetics were sampled through force plate and linear position transducers. Resistance-trained produced greater overall force, velocity, and power; however, similar patterns were observed in all variables when comparing conditions. Cluster sets produced significantly greater force in isolated repetitions in sets 1-3, while consistently producing greater force due to a required reduction in load during set 4 resulting in greater total volume load (CLU, 3302.4 ± 102.7 kg; TRD, 3274.8 ± 102.8 kg). Velocity loss was lessened in CLU resulting in significantly higher velocities in sets 2 through 4. Furthermore, higher velocities were produced by CLU during later repetitions of each set. Cluster sets produced greater power output for an increasing number of repetitions in each set (set 1, 5 repetitions; sets 2 and 3, 6 repetitions; set 4, 8 repetitions), and the difference between conditions increased over subsequent sets. Time under tension increased over each set and was greater in TRD. This study demonstrates greater power output is driven by greater velocity when back squatting during CLU; therefore, velocity may be a useful measure by which to assess power.

Acute response to cluster sets in trained and untrained men

“…Therefore, this study expands on our recent study examination of the kinetic and kinematic differences between TRD and CLU in RT and UT men (Oliver et al 2015) by examining the differences in those factors, mechanical, metabolic, and hormonal; that have been identified as potential contributors to the mechanism(s) responsible for differing adaptations observed between TRD and CLU. In following with our recent report (Oliver et al 2015), a secondary purpose was to examine if differences exist between trained and untrained males.…”

“…These data are those in which blood samples were able to be obtained. Data associated with the larger sample examining differences in the kinetics and kinematics of CLU and TRD is published elsewhere (Oliver et al 2015).…”

“…In following with our recent report (Oliver et al 2015), a secondary purpose was to examine if differences exist between trained and untrained males. With TRD, we hypothesized greater metabolic stress with a resultant larger hormonal response; whereas, CLU would attenuate the decline in power attributed to TRD.…”

Acute Effect of Cluster and Traditional Set Configurations on Myokines Associated with Hypertrophy

“…Cluster sets (CLU) incorporate a brief rest (typically 15-30 s) between individual repetitions (inter-repetition rest) or group of repetitions (intra-set rest) with a set of resistive exercises. In contrast to traditional set configurations (TRD), which result in an almost linear decrease in force [9,24], velocity [9,24], and power [9,16,23], CLU maintain and/or attenuate the loss in power [9,16,23], primarily due to higher velocities [24]. This is facilitated by the ability of the phosphagen and glycolytic energy systems to recover during the brief rest periods as evidenced by lower blood lactate [5,6,23] following CLU compared to TRD, as well as greater intramuscular adenosine triphosphate (ATP) and phosphocreatine (PCr) [6].…”

“…This is facilitated by the ability of the phosphagen and glycolytic energy systems to recover during the brief rest periods as evidenced by lower blood lactate [5,6,23] following CLU compared to TRD, as well as greater intramuscular adenosine triphosphate (ATP) and phosphocreatine (PCr) [6]. However, although the beneficial effects of CLU in the acute setting are unequivocal [9,16,24], long-term studies have failed to produce results superior to TRD [8,33], except when training was performed at or around the optimal load [22]. Following a 12-week periodized program designed to elicit hypertrophy, greater gains in strength and power were observed following CLU compared to TRD [22], likely due to neuromuscular adaptations (i. e., increase recruitment of type II fibers) [14] resulting from differences in mechanical stress [3].…”