Free weights vs. machines
// What the research shows
The meta-analysisMeta-analysis A study of studies: the results of many individual studies are pooled statistically. More in the glossary → by Haugen et al. (2023; 13 studies, 1,016 participants) found no difference between free weights and machines in direct comparisons, neither for hypertrophy nor for strength or jump height. Strength was exercise-specific, though: free-weight trainees improved clearly more in free-weight tests than the machine group, with a trend the other way for machine tests.
// In practice
- For hypertrophy: use whatever suits you and lets you train hard and safely.
- If you want a specific lift stronger (e.g. the squat for powerlifting), train that lift.
- Mixing works well: heavy compounds with free weights, machines for targeted volumeTraining volume Usually measured as the number of hard sets per muscle per week. More in the glossary → close to failureMuscular failure The point where, despite full effort, you can't complete another clean rep. More in the glossary →.
// Limitations & open questions
Only 5 of the 13 studies measured hypertrophy, so data there are thin. Participants were 18–60 years old.
// Sources
// More from Training
Training volume
More hard sets per muscle per week lead to more growth, but each extra set adds a bit less than the one before.
Training frequency
For muscle growth it doesn't matter much how many days you spread your sets over. For strength, practising the lift more often helps.
Proximity to failure (RIR)
For muscle growth it pays to train close to failure. For strength it matters much less.
Load & rep range
Muscles grow similarly with light and heavy loads as long as sets are hard. Maximal strength needs heavy loads.