Free weights or machines?
Short answer
For muscle growth the analysis found no clear difference; choose what lets you train cleanly and consistently. Strength rises mainly in the form you train. If you want a better barbell lift, train that lift.
Figures
- 13 · studies with 1,016 adults (Haugen 2023)
- p = 0.751 · muscle growth: no difference
- 5 · studies measured muscle growth
- -0.055 (95% CI: -0.397–0.287) effect size: Muscle growth
- 0.084 (95% CI: -0.106–0.273) effect size: Strength, direct comparison
- -0.21 (95% CI: -0.391–-0.029) effect size: Strength in free-weight tests
- 0.291 (95% CI: -0.017–0.6) effect size: Strength in machine tests
What the analysis shows
Haugen and colleagues found no difference in strength, jump height or muscle growth in direct comparison. People who trained with free weights got stronger in free-weight tests; people who trained on machines tended to get stronger on machines. The ACSM position stand also found no consistent effect of equipment type.
How to use it
Machines are handy for targeting a muscle and controlling the movement. Free weights pay off when a specific lift such as the squat or bench press matters to you. Most plans mix both.
Limits
Only 5 studies measured muscle growth, and participants were mostly men. The analysis says little about single muscles or exercises.
Sources
- Effect of free-weight vs. machine-based strength training on maximal strength, hypertrophy and jump performance - a systematic review and meta-analysis. · Haugen · 2023 · BMC Sports Science, Medicine and Rehabilitation PubMed DOI Study note
- American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews · Currier · 2026 · Medicine & Science in Sports & Exercise PubMed DOI Study note
Summaries by SetCtl, not medical advice.