Machines VS Free Weights For Muscle Building

Ahhhh…one of the classic debates in muscle building.  Many old school lifters will tell you free weights are the most effective way to build muscle, while more recent generations have begun to embrace more machine-based training.  So…which method is better for putting that muscle on?  Let’s take a look at what the science says…

Traditionally, it has been thought that free weights are a superior method for stimulating muscle growth compared to machines, partially due to the increase in muscle recruitment in free weight exercises.  In essence, more muscles are needed to help stabilize the primary muscles during lifts.  

Recent studies suggest, however, that although there is indeed more muscle recruitment, it does not lead to an increase in muscle size compared to performing similar exercises on a machine.  In fact, in a study done in 2020, where 2 groups were measured on muscle growth over a period of 8 weeks, with one group performing only free weight exercises(measured exercises were squat and bench press) and one group performing only machine exercises(smith machine squat and smith machine bench press), there was no statistical difference in muscle gain between the 2 groups.  Older studies have shown similar results as well.  Training age has also been tested, and studies where participants have been resistance training for at least 2 years, and those who are just beginning their fitness journey, showed similar muscle growth results no matter which method of training(free weight, machine) they employed.

I believe a combination of both free weight and machine exercises will provide the best results, as although both build similar amounts of muscle, each does have their own specific advantages: 

Benefits of free weights

-Recruits stabilizing muscles

-Proper form is a MUST

-Free weights allow for a variety of exercises with limited equipment

-Full range of motion throughout the movement & natural range of motion

Benefits of machines

-Allows specific isolation of muscles

-Can follow the strength curve of the muscle being worked

(The movement remains consistently difficult from beginning to end)

-More time efficient

-Machines have safety measures that allow you to lift without the aid of a spotter

Int. J. Environ. Res. Public Health 2020, 17(21), 7848; https://doi.org/10.3390/ijerph17217848

J Strength Cond Res 2020 Jul;34(7):1851-1859.doi: 10.1519/JSC.0000000000003349.