The Acute Neuromuscular Responses to Cluster Set Resistance Training: A Systematic Review and Meta-Analysis

Abstract

Background: Cluster sets (CSs) are a popular resistance training (RT) strategy categorised by short rest periods implemented between single or groups of repetitions. However, evidence supporting the effectiveness of CSs on acute intra-session neuromuscular performance is still equivocal.

Objective: The objective of this investigation was to determine the efficacy of a single session of CSs to attenuate losses in force, velocity and power compared to traditional set (TS) training.

Methods: Screening consisted of a systematic search of EMBASE, Google Scholar, PubMed, Scopus and SPORTDiscus. Inclusion criteria were (1) measured one or more of mean/peak force, velocity or power; (2) implemented CSs in comparison to TSs; (3) an acute design, or part thereof; and (4) published in an English-language, peer-reviewed journal. Raw data (mean ± standard deviation) were extracted from included studies and converted into standardised mean differences (SMDs) and ± 95% confidence intervals (CIs).

Results: Twenty-five studies were used to calculate SMD ± 95% CI. Peak (SMD = 0.815, 95% CI 0.105-1.524, p = 0.024) and mean (SMD = 0.863, 95% CI 0.319-1.406, p = 0.002) velocity, peak (SMD = 0.356, 95% CI 0.057-0.655, p = 0.019) and mean (SMD = 0.692, 95% CI 0.395-0.990, p < 0.001) power, and peak force (SMD = 0.306, 95% CI - 0.028 to 0.584, p = 0.031) favoured CS. Subgroup analyses demonstrated an overall effect for CS across loads (SMD = 0.702, 95% CI 0.548-0.856, p < 0.001), included exercises (SMD = 0.664, 95% CI 0.413-0.916, p < 0.001), experience levels (SMD = 0.790, 95% CI 0.500-1.080, p < 0.001) and CS structures (SMD = 0.731, 95% CI 0.567-0.894, p < 0.001) with no difference within subgroups.

Conclusion: CSs are a useful strategy to attenuate the loss in velocity, power and peak force during RT and should be used to maintain neuromuscular performance, especially when kinetic outcomes are emphasised. However, it remains unclear if the benefits translate to improved performance across all RT exercises, between sexes and across the lifespan.

Fig. 1

Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) flowchart of literature search strategy. TS traditional set

Fig. 2

An example of each of the general resistance training paradigms (traditional sets and cluster sets) used in the literature. Cont. continue, Rep repetition

Fig. 3

Standardised mean difference, upper and lower confidence limit (95% confidence interval), and p value of each individual study and overall effect for a mean and peak force, b mean and peak velocity, and c mean and peak power. Significance indicated by p < 0.05. No difference in kinetic variables (i.e. between force, power and velocity) were observed between traditional set and cluster set training. CI confidence interval, diff difference, SMD standardised mean difference, Std standard

Fig. 4

Standardised mean difference, upper and lower confidence limit (95% confidence interval), and p value of each individual study and overall effect for a exercise type, b loading strategy, c resistance training experience and d cluster set protocol. Significance indicated by p < 0.05. No differences were observed between outcomes in any subgroup. CI confidence interval, diff difference, SMD standardised mean difference, Std standard, WL weightlifting

Fig. 4

Standardised mean difference, upper and lower confidence limit (95% confidence interval), and p value of each individual study and overall effect for a exercise type, b loading strategy, c resistance training experience and d cluster set protocol. Significance indicated by p < 0.05. No differences were observed between outcomes in any subgroup. CI confidence interval, diff difference, SMD standardised mean difference, Std standard, WL weightlifting