The Study
Machines and free weight exercises: a systematic review and meta-analysis comparing changes in muscle size, strength, and power.
This study looked at lots of other studies and found that if you train with free weights, you get better at doing free weight exercises — and if you train with machines, you get better at machine exercises. But it doesn’t prove one is better overall — just that you get better at what you practice.
Analysis score
Maximum 100 for a systematic review with meta-analysis.
Where the score came from
If you train with free weights, you'll get stronger at free weights. If you train with machines, you'll get stronger at machines. But both are equally good for building muscle and power.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 533 / 100
Quality score
The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — if you care about performing well on a specific type of lift (e.g., barbell squat vs.
- 2leg press), choose the matching training.
- 3For general fitness, either works equally well.
- 4Free-weight training: +0.655 strength gain on free-weight tests.
- 5Machine training: -0.784 strength gain on machine tests.
- 6No difference in muscle growth (-0.01) or power (-0.049).
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of sports medicine and physical fitness
Year
2021
Authors
Kyle A Heidel, Z. Novak, S. Dankel
Related Content
Claims (6)
If you lift weights with machines or with free weights and do the same amount of work at the same effort level, you’ll build muscle just as well with either one — even if you’re already fit.
If you train using weight machines and then test your strength on machines, you’ll get stronger than if you trained with free weights — but only because the test matches the training. It’s like practicing basketball shots from the free-throw line and then being tested there: you’ll do better than if you practiced elsewhere.
If you measure strength with a tool that doesn’t favor free weights or machines, both kinds of workouts—free weights and machines—help you get just as strong. The difference between them is so small it might just be due to chance.
Lifting free weights and using weight machines both help you get stronger just about the same amount—neither one is clearly better for boosting your explosive power.
If you want to get stronger at lifting weights like dumbbells or barbells, training with those same free weights will help you gain more strength than using machines — because your body gets better at the exact movements you practice.
Lifting free weights and using weight machines both help you build muscle in about the same way—neither one is clearly better than the other.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.