BACKGROUND: The alteration of individual sets during resistance training (RT) is often used to allow for greater velocity and power outputs, reduce metabolite accumulation such as lactate and also reduce perceived exertion which can ultimately affect the resultant training adaptations. However, there are inconsistencies in the current body of evidence regarding the magnitude of the effects of alternative set structures (i.e., cluster sets and rest redistribution) on these acute mechanical, metabolic, and perceptual responses during and after RT. OBJECTIVE: This study aimed to systematically review and meta-analyse current evidence on the differences between traditional and alternative (cluster and rest redistribution) set structures on acute mechanical, metabolic, and perceptual responses during and after RT, and to discuss potential reasons for the disparities noted in the literature. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and five databases were searched until June 2019. Studies were included when they were written in English and compared at least one acute mechanical, metabolic, or perceptual response between traditional, cluster or traditional and rest redistribution set structures in healthy adults. Random-effects meta-analyses and meta-regressions were performed where possible. RESULTS: Thirty-two studies were included. Pooled results revealed that alternative set structures allowed for greater absolute mean [standardized mean difference (SMD) = 0.60] and peak velocity (SMD = 0.41), and mean (SMD = 0.33) and peak power (SMD = 0.38) during RT. In addition, alternative set structures were also highly effective at mitigating a decline in velocity and power variables during (SMD = 0.83-1.97) and after RT (SMD = 0.58) as well as reducing lactate accumulation (SMD = 1.61) and perceived exertion (SMD = 0.81). These effects of alternative set structures on velocity and power decline and maintenance during RT were considerably larger than for absolute velocity and power variables. Sub-group analyses controlling for each alternative set structure independently showed that cluster sets were generally more effective than rest redistribution in alleviating mechanical, metabolic, and perceptual markers of fatigue. CONCLUSION: Alternative set structures can reduce mechanical fatigue, perceptual exertion, and metabolic stress during and after RT. However, fundamental differences in the amount of total rest time results in cluster sets generally being more effective than rest redistribution in alleviating fatigue-induced changes during RT, which highlights the importance of classifying them independently in research and in practice. Additionally, absolute values (i.e., mean session velocity or power), as well as decline and maintenance of the mechanical outcomes during RT, and residual mechanical fatigue after RT, are all affected differently by alternative set structures, suggesting that these variables may provide distinct information that can inform future training decisions. PROTOCOL REGISTRATION: The original protocol was prospectively registered (CRD42019138954) with the PROSPERO (International Prospective Register of Systematic Reviews).

• MeSH
• Adult MeSH
• Lactic Acid blood   MeSH
• Humans MeSH
• Rest * MeSH
• Resistance Training methods   MeSH
• Physical Exertion MeSH
• Fatigue * MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Publication type
• Journal Article MeSH
• Meta-Analysis MeSH
• Systematic Review MeSH
• Names of Substances
• Lactic Acid MeSH

This study determined whether redistributing total rest time into shorter, but more frequent rest periods could maintain velocity and power output during 3 traditional sets of 6 clean pulls using 80% (TS80), 100% (TS100) and 120% (TS120) of power clean 1RM with 180 seconds of inter-set rest and during 3 "rest redistribution" protocols of 9 sets of 2 clean pulls using 80% (RR80), 100% (RR100) and 120% (RR120) of power clean 1RM with 45 seconds of inter-set rest. The total number of repetitions performed above 10 and 20% velocity loss thresholds, mean and peak velocity maintenance (the average of all 18 repetitions relative to the best repetition; MVM, PVM), and decline (the worst repetition relative to the best repetition; MVD, PVD) were calculated. For MVM, PVM, MVD, and PVD, there were small-to-moderate effect sizes in favour of RR80 and RR100, but large effects favouring RR120, compared to their respective TS protocols. The number of repetitions within a 20% velocity loss threshold was 17.7 ± 0.6 during RR and 16.5 ± 2.4 during TS (effect size 0.69); and the number of repetitions within a 10% velocity loss threshold was about 13.1 ± 3.7 during RR and 10.7 ± 3.6 during TS (effect size 0.66). Therefore, RR generally allowed for a better overall maintenance of velocity and power, especially at heavy loads. Coaches who wish to implement velocity-based training, but who do not wish to purchase or use the associated equipment, may consider rest-redistribution to encourage similar training stimuli.

• Keywords
• cluster sets, fatigue, power, resistance training, traditional sets, weightlifting,
• Publication type
• Journal Article MeSH