ReviewJournal of human kinetics2026
Comparison of Muscle Activation between Variable Resistance Training and Free Weight Training: A Systematic Review and Meta-Analysis.
Review in Journal of human kinetics, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
2 citing papers in PubMed, 1 synthesis or guideline pooled it.
- The Effect of Variable Resistance Training on Post-Activation Performance Enhancement: A Systematic Review and Three-Level Meta-analysis.Sports medicine - open · 2026Pooled it
- Load-velocity relationship during chain-based variable resistance in the smith machine back squat.BMC sports science, medicine & rehabilitation · 2026Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Variable resistance training (VRT) can address biomechanical limitations of free weight training (FWT) and enhance performance, but its effect on muscle activation remains unclear. This study aimed to compare muscle activation between VRT and FWT, focusing on the impact of variable resistance load proportions and contraction phases in VRT. A systematic review was conducted using PubMed, Scopus, SPORTDiscus, and Web of Science, including studies of healthy adults with at least six months of training experience performing multi-joint exercises. Muscle activation was measured using surface electromyography (sEMG), and Standardized Mean Differences (SMD) were calculated using a random-effects model. The meta-analysis of 11 studies found no significant overall difference between VRT and FWT (SMD = 0.07; p = 0.493). However, VRT showed greater activation during the concentric phase than both the eccentric phase (SMD = 1.40; p < 0.001) and the FWT's concentric phase (SMD = 0.32; p = 0.033). Higher variable resistance load proportions in VRT also resulted in greater activation than FWT at equivalent loads (SMD = 0.38; p = 0.036). Thus, under the same load, VRT significantly improves concentric-phase muscle activation over FWT, with higher variable resistance loads providing even greater benefits.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.