A new meta-analysis sought to determine if free-weight or machine-based training is better for strength, hypertrophy and power outcomes.

In this short blog we’ll discuss using free weights vs machines. Which should we spend more time on to get the results we want, in the least amount of time?

In our efforts to improve our physical performance and appearance we often look for the best protocols to get us there.

The best set and rep schemes, the best periodization methods, the best lifts to perform, the optimal frequency to hit each muscle, etc..

Data certainly points to what is optimal in many of these adaptations we’re after.

However, “optimal” is not always as specific as we want it to be. Otherwise said, we often look for black and white answers – do this, not that – when in reality, there rarely ever are any black and white answers. It’s not how nature works.

What’s the optimal number of reps performed per set to increase hypertrophy? Well, the data points to anywhere from 5-30 reps as being adequate to produce hypertrophy. That’s a pretty large range. And does that mean that doing sets of 4 reps won’t produce any changed in muscle size? Of course it will!

The data we have simply points to best practices.

Lets see what best practices come from this 2021 meta-analysis…


The reviewed meta-analysis from Heidel et al examined the differences in hypertrophy, strength, and power gains when training with machines versus free weights.

Overall, the findings were unsurprising.

Free-weight training was better for increasing strength with free weights, and machine-based training was better for increasing strength with machines. This is obvious, you get stronger at the movements you practice.

Further, strength gains were similar when strength was tested using a modality not trained by either group.

Changes in both power and muscle growth were similar between free-weight and machine-based training.

Overall, these findings reinforce the principle of specificity regarding strength gains, and suggest that those primarily interested in muscle growth can choose a modality based upon preference. 


Strength is specific to the exercise you train. If you want a stronger squat, then….squat.

Muscle growth is achieved through mechanical which means it increased to the same degree regardless of modality. Meaning picking between free weights or machines shouldn’t be too much of a concern.

Here we can go into Stimulus to Fatigue Ratio (SFR) which is the amount of muscle building adaptations an exercise can give you relative to the fatigue it forces you to recover from.

If maximal hypertrophy is your goal then choosing exercises with a low SFR may take priority.

A snatch grip deadlift from a deficit is a great exercise but creates TONS of systemic fatigue, leaving you drained while you complete the rest of your workout. This may not be ideal if maximal hypertrophy is your goal.

This is where having a goal, a specific adaptation you are after, is imperative. A competitive powerlifter who needs big numbers in the squat, bench press, and deadlift, needs to spend a LOT of time squatting, pressing, and deadlifting.

We get better at that which we practice. Be as specific as possible in defining WHAT you want to get better at, WHAT you want to improve on. This is imperative, especially for the seasoned lifter.

Overall this meta-analysis is relatively good news for the general practitioner, as they offer flexibility when selecting a resistance training modality.

Key Takeaways

  1. The presently reviewed meta-analysis sought to determine if free-weight or machine-based training is better for strength, hypertrophy, and power outcomes.
  2. The researchers found that strength gains are best achieved when the exercise tested is the exercise that was trained. Further, researchers found that strength gains on a “neutral” modality (not trained in either group) were similar between free weight and machine training, as were muscle growth and power gains.
  3. Overall, the findings of this meta-analysis are intuitive. You need to train with free weights if you want to maximize strength on a free-weight exercise, and vice versa for machines. Since findings showed similar rates of muscle growth between training modalities, bodybuilders and general trainees should use the type of training they prefer and can adhere to.