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Strength & hypertrophy: free-weights or machines?

by P. Debraux | 5 September 2023

strength, hypertrophy, science, sport, fitness, training, muscle, mass

Resistance training is the best way to gain muscle strength and mass. However, for training to bear fruit and to optimize results, it is essential to manipulate several variables correctly, such as training frequency, volume, intensity, load, rest between sets, execution speed, type of contraction, range of motion, type of resistance and the choice and order of exercises.

Among these options, it is also possible to choose to train with free-weights or with machines. In fitness, there is much debate, and of course, this choice has been the subject of long discussions. Free-weights are often considered better, as they would involve greater motor activation of the agonist/synergist muscles, and would also enable the core muscles to be recruited to a much greater extent. However, those who advocate the use of machines argue that the activation of core muscles, and therefore the energy required to perform a free-weight exercise, would reduce the energy allocated to the targeted muscles. This, in turn, would have an impact on muscle mass gains.

Yet some meta-analyses have found no difference in strength and hypertrophy gains between machine and free-weight training. But it's important to be aware that protocols often don't allow for real comparison. Some studies compare a squat to a leg extension or a leg press, while others limit the experimental protocol to a single exercise. But is there a real difference between these two types of resistance?

The Study

In an attempt to provide a clearer answer to this question, a team of Spanish researchers compared gains in strength and hypertrophy after 8 weeks of training based exclusively on machines or with free-weights. To do this, the researchers recruited 36 weight-trainers and divided them into 2 groups: "Machines" and "Free-weights".

For each group, the training program consisted of 4 exercises, with 3 sets per exercise and 4 minutes rest between sets. Velocity-Based Training (VBT) was used to ensure that all exercisers completed the same training volume with the same intensity. The 4 free-weight exercises chosen were the squat, bench press, military press and prone bench pull. For the "Machines" group, the researchers chose a hack squat machine, a horizontal press, a vertical shoulder press and a horizontal pull machine.

Before and after the 8-week protocol, the researchers analyzed hypertrophy gains via ultrasound in the quadriceps (2 sites), pectoralis major and rectus abdominis. For strength, all participants performed a 1RM test on all 8 exercises (the 4 free-weight variants and the 4 machine variants). From these results, they were able to obtain several variables, such as 1RM relative to body mass, and average concentric propulsion speed. Finally, the researchers also analyzed discomfort via 2 validated questionnaires on pain, stiffness and physical disability.

Results & Analyzes

The main results of this study show that whatever the training mode (machines vs. free-weights), both groups achieved similar improvements in strength, hypertrophy and joint discomfort. Bearing in mind that the exercises compared here are very similar in terms of movement patterns and amplitude.

Each group achieved the greatest gains in strength on the exercises on which they had trained for 8 weeks (although they also improved on those on which they had not trained). In terms of hypertrophy, the 2 groups gained in volume, much more in the pectoralis major than in the quadriceps and rectus abdominis. Finally, joint discomfort was reduced following the 8-week training protocol.

Practical Applications

The supposed superiority of free-weights over muscle strength or hypertrophy, quite widespread among fitness enthusiasts, is mainly based on longitudinal studies in which the final test is carried out only with free-weight exercises, or non-longitudinal studies attributing greater muscular activity to free-weights. Nevertheless, numerous studies have shown that greater myoelectric activity does not necessarily reflect better long-term gains.

Taken together, these results suggest that training modalities with free-weights or machines are just as effective in promoting strength and hypertrophy without increasing joint discomfort. Consequently, you can promote these adaptations by training with either of these two modalities, according to your possibilities or preferences, without thinking that one method or the other is "better"... Especially as this would allow you to focus on other training parameters that have been widely demonstrated to be key, such as training volume and frequency, intensity, or exercise choice.


  1. Hernández-Belmonte A., Martínez-Cava A., Buendía-Romero A., Franco-López F. and Pallarés J.G. Free-Weight and Machine-Based Training Are Equally Effective on Strength and Hypertrophy: Challenging a Traditional Myth. Med Sci Sports Exerc Published ahead of print.

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