Is one better than the other? Let’s find out👇

First, let’s start off with the advantages of using free weights:

1. Greater fiber activation: Greater neuromuscular activation, heavily due to the requirement of stabilizer activation. A great example would be the barbell squat, requiring activation from the core, lumbo-pelvic-hip-complex, as well as the target musculature in the lower extremities. 
2. Functionally driven: Mimicking real life movements as well as athletic movement. 
3. Increased ROM: Natural movement path, allowing for increased ranges. I could argue that there are ways to increase ROM on machines as well, but free weight is by far more superior when it comes to increased ROM integration.
4. Boost in strength: Free weights have been known to elevate overall strength development, especially in compounds. 
5. Large variations: There is so much you can do with free weight! Involve multiple joints with less equipment.
6. Increased core activation/engagement: This leads to boosted functional strength

What about the advantages of selectorized machinery?

1. Greater ability to target or concentrate specific musculature: Decrease stabilizer requirements, allowing for the focus to be allocated towards the target muscle. Not allowing secondary musculature to become a limiting factor.
2. Ability for constant tension: Unlike free weights, cams & pulley systems allow for consistent resistance throughout all phases of the motion. 
3. Ability to increase volume: Less stabilization = less fatigue. 
4. Failure: Train closer to failure safely. 
5. Decreased risk of injury: Fixed movement path! Less chance of unnecessary stress on joints & tendons. 
6. Ability to progressively overload @ a higher efficiency: Increase by precise increments. Allow for easy tracking ability!
7. Less neurological demand: Higher training frequency, better recovery. 
8. Key for body-building or hypertrophy based training. 

Let’s simplify: 

Free weights superiority: Muscle activation, strength, functional movement, range of motion, athleticism, imbalance correction. 

Selectorized machinery superiority: Better target muscle concentration, safety, recovery, failure training, constant tension, time under tension. (Pure hypertrophy)

But, the truth is, combining both is much more effective. This is unless your goals require favoring one side. Experience & preference also comes into play as well. By integrating both free weights and machines, you gain the best of both worlds—functional strength, muscle isolation, injury prevention, and hypertrophy. This hybrid approach ensures balanced development, long-term progression, and sustainable muscle growth. 

Here are some supporting peer reviewed research articles to support the information above: 

Strength adaptations were specific to the training modality used, suggesting that incorporating both free weights and machines could provide a more balanced development of strength and muscle mass. bmcsportsscimedrehabil.biomedcentral.com

free-weight and machine-based modalities are similarly effective in promoting strength and hypertrophy without increasing joint discomfort. This finding supports the idea that utilizing both methods can enhance training variety and potentially reduce the risk of overuse injuries associated with repetitive movements. 

pubmed.ncbi.nlm.nih.gov

The study concluded that strength adaptations are specific to the training modality, and the choice between free weights and machines should align with individual preferences and goals.

pmc.ncbi.nlm.nih.gov

The study found that machines equipped with load selectors (selectorized machines) demonstrated effective muscle activation, comparable to traditional machines, suggesting their efficacy in strength training.

pmc.ncbi.nlm.nih.gov

My clinical scenario comprehensive final on the difference between the two in comparison to hypertrophy:https://docs.google.com/document/d/1k_m-lW66ZxRroPcJSb4osR8NNHbNUWPtjGvd_av32LI/edit