Free Weights vs Machines
The number of excellent scientific studies on exercise has been growing, and I read one this past week that was relevant and useful to everyone.
For those that dont know, the argument of free weights being better than machines has raged on and on for years in fitness.
People that advocate for free weights will argue that barbells and dumbbells are superior because they use more small muscle stabilizers, and by extension they are more "functional".
The other typical claim made is free weights build more muscle, and they also build more or better or more functional strength.
On the other hand, you have machines. The purpose of using machines is to lower the stability demands, which hypothetically allows for more targeted mechanical tension and loading of the respective muscles. The design of machines allows for direct targeting of major muscles and with loading potential that can exceed that of free weight movements.
In practice, most trainers and coaches occupy a Middle ground
Context created, what did this Meta-analysis tell us?
This particular Meta-Analysis was done in Norway. They grouped together 13 studies, and looked at increases in maximal strength, hypertrophy, and counter movement jump performance (a fancy name for vertical jump).
The studies overall had 1,016 people, 789 men and 219 women. 6 studies were trained individuals, while 7 of them were novices. The average length of the studies was about 9 weeks. (so 2 months of training)
Overall it was a good sample size. To make training observations and recommendations, the more people the better.
So what did they find?
Hypertrophy: NO DIFFERENCE. . Both machines and free weights built equal amounts of muscle, with not statistical difference seen in the outcomes. For muscle building purpose, we can say that free weights and machines are on par with each other, and usage is individual preference
Strength: Increases in strength were specific to the training implement used. Meaning free weight people got stronger with free weight exercises, but not machines. Machine people got stronger with machines, but not much with free weights. Nothing was particularly surprising about this. Strength is movement specific, you get stronger at what you practice
Isometric Strength: NO DIFFERENCE. This was the most interesting and breaks down the free weight bias. Isometric strength tests involve exerting maximum muscle contraction against an immovable object, isometric chest press, isometric pulldown, iso leg press, etc.
These tests can be done by anyone and are considered a good proxy for nonspecific "functional" strength. Weak people cannot contract their muscles very well. Strong people can.
This tells us that you are looking for general strength and quality of life improvements, machines or free weights can be used.Jump Height: This is where the results finally showed some slight bias, as free weights produced slightly greater improvements, but both free weights and machines led to improvement regardless and the differences were not considered statistically significant.
Interestingly, in one of the machine studies (Schwartz et al study), the women doing hack squats had better improvements in vertical jump compared to the free weight group. And in that study both groups practiced jumping.
Considering that jumping is a specific physical skill, it makes sense that freeweight exercises that closer resemble a standing vertical jump could work better for increasing skill specific strength. At the same time, the body position can also potentially be mimicked with a machine squat, and we know that both are viable options.
Overall, we can consider Machines and Freeweights to be EQUAL in their effectiveness
A productive program uses the best tools for the job at hand.
Context of application matters more than dogma.