Variable resistance training (VRT) means changing the load during a repetition, most often by hanging chains from a barbell or looping elastic bands over it, so that resistance rises as the lift is completed. The equipment is sold on the promise of extra strength and power. This article summarises the abstracts of four meta-analyses published between 2015 and 2026 and states what each can and cannot support. Their conclusions differ, which is itself informative. It is general information about training equipment, not medical advice.
Meta-analysis one: seven studies, 235 people (2015)
Soria-Gila and colleagues, in the Journal of Strength and Conditioning Research (2015), pooled seven studies with 235 subjects. They compared long-term programmes of at least seven weeks that used chains or elastic bands with similar programmes using constant resistance, in trained adults from different sports and in untrained people, looking at one-repetition maximum (1RM). VRT produced a significantly greater mean strength gain, a weighted mean difference of 5.03 kg (95 per cent confidence interval 2.26 to 7.80 kg). The authors concluded that long-term VRT with chains or bands attached to the barbell is an effective method of improving maximal strength.
Meta-analysis two: 17 studies, 491 people (2022)
Andersen and colleagues, in the Journal of Science and Medicine in Sport (2022), pooled 17 studies with 491 healthy adults (341 men and 150 women, aged 18 to 37) comparing VRT with traditional resistance training. For maximal strength there were no statistically significant differences between the two for the lower body (p = 0.46, standardised mean difference -0.10) or the upper body (p = 0.14, -0.17). Nor were there significant differences in muscle power for the lower body (p = 0.16, 0.21) or upper body (p = 0.81, 0.05). One sub-group analysis found larger lower-body strength gains after traditional training when more repetitions per set were used. The authors concluded that the two approaches are equally effective for maximal strength and power in healthy adults.
Meta-analysis three: elastic tubes against conventional devices (2019)
Lopes and colleagues, in SAGE Open Medicine (2019), examined a different comparison: training with elastic devices (tubes and Thera-Bands) against conventional devices (weight machines and dumbbells). Eight studies were included. There was no superiority for either method for lower-limb strength (standardised mean difference -0.11, 95 per cent confidence interval -0.40 to 0.19) or upper-limb strength (0.09, -0.18 to 0.35). The authors concluded that elastic resistance can promote similar strength gains to conventional resistance. This review is about stand-alone elastic devices, not bands attached to a barbell, so it should not be read as a verdict on barbell VRT.
Meta-analysis four: a 2026 comparison with free weights
Li and colleagues, in the Journal of Strength and Conditioning Research (2026), compared VRT with free weight training for maximal strength, velocity, power and jump distance, in long-term and acute interventions. The authors used cluster analysis to group studies by the proportion of load that was variable (VRLP). For long-term effects, VRT outperformed free weights for maximal strength and jump distance, with standardised mean differences between 0.28 and 0.37. Chain-based loading and a variable load of 20 per cent or less showed advantages for both (0.39 to 0.51). Multiple-exercise VRT improved maximal strength (0.27), while single-exercise VRT improved jump distance (0.46). For acute effects, a variable load above 20 per cent showed greater maximal force output, and above 37 per cent produced lower movement velocity and power compared with free weights. The authors concluded that long-term VRT surpasses free weight training for maximal strength and jump distance, and that chain-based loading or a variable share of 20 per cent or less appears optimal.
Why the results differ
- Different pools of studies. The 2015 review included seven studies of barbell chains or bands; the 2022 review included 17 studies of variable against traditional training; the 2026 review categorised studies by how much of the load was variable.
- Different questions. The 2019 review compared elastic tubes against machines and dumbbells, which is not the same as adding bands to a barbell.
- Effect sizes are small to moderate. Where a benefit was found, it was a few kilograms on a 1RM test or a standardised difference of roughly 0.3 to 0.5. Small differences on short-term tests do not show what happens over years of training.
What the evidence does not show
None of the abstracts reports injury outcomes, and none supports a claim that VRT builds more muscle. The subjects were mainly healthy adults aged 18 to 37 in the 2022 review, so the findings should not be extended to older adults or beginners without a specific study. The abstracts also do not say whether a particular brand of chain or band performs better.
Practical points for a home set-up
- The 2022 and 2019 reviews found no meaningful gap between variable and traditional or conventional training for maximal strength, so bands and chains are an optional extra and not a required purchase.
- Where a lifter wants to try them, the 2026 review suggests keeping the variable share modest, at 20 per cent or less of the load for long-term training.
- Barbell bands and chains are used with a barbell and rack; the guides to rack dimensions and rack safety systems cover what to check.
- Stand-alone bands are a different product category, discussed in the guide to resistance bands and suspension trainers.
- For ways to keep progressing without new kit, see progressive overload at home.
The bottom line
Meta-analyses disagree. The 2015 and 2026 reviews found small advantages for bands and chains on 1RM and jump distance, while the 2022 review found no significant differences from traditional training and the 2019 review found elastic tubes comparable to conventional devices. Any benefit is small, and none of the reviews shows that bands or chains build more muscle or reduce injury. Anyone who already trains hard with a plain barbell has no clear evidence-based need to add them.
Sources
- Soria-Gila et al., “Effects of Variable Resistance Training on Maximal Strength: A Meta-Analysis”, Journal of Strength and Conditioning Research (2015)
- Andersen et al., “Comparing the effects of variable and traditional resistance training on maximal strength and muscle power in healthy adults: A systematic review and meta-analysis”, Journal of Science and Medicine in Sport (2022)
- Lopes et al., “Effects of training with elastic resistance versus conventional resistance on muscular strength: A systematic review and meta-analysis”, SAGE Open Medicine (2019)
- Li et al., “Comparison of Variable Resistance and Free Weight Training on Long-Term and Acute Effects on Different Assessments of Strength: A Systematic Review and Meta-Analysis”, Journal of Strength and Conditioning Research (2026)