March 5, 2026, 12:58 pm | Read time: 4 minutes
Anyone who likes going to the gym and works out regularly has probably asked themselves the question: Is training with free weights or on machines more effective for building muscle? It’s a controversial question that a study has now clearly answered.
When it comes to strength training, there are numerous methods that, when used correctly, effectively promote muscle and strength building. While some prefer training with their own body weight, known as bodyweight training, others tend to train their muscles by lifting heavy weights such as dumbbells. Beginners and older people in particular often tend to train on machines, as they offer a degree of protection against injury due to their fixed trajectory and are considered easy on the joints. Even Arnold Schwarzenegger has now discovered training on machines for himself. However, the question is always being debated: Is equipment training just as effective in terms of muscle building as training with free weights? A Spanish study has looked into this question and has come to a surprising conclusion.
Overview
Researchers Clarify the “Eternal” Weight Training Question
In order to clarify the controversial weight training question, Spanish scientists recruited 36 male strength athletes.1 They all had to complete an eight-week training program. They were randomly divided into two training groups: One group used equipment, the other exclusively free weights to build muscle. The scope, intensity, and muscle groups used were exactly the same in both training groups. The following exercises were performed with free weights:
- squats
- bench press
- bench pull
- shoulder presses
The equipment group had to use different machines to train the same muscle groups. All test subjects trained three times a week with three sets of each exercise and four-minute breaks. The intensity was between 65 and 85 percent of maximum strength. The recovery phase after each training session was at least 48 hours.
Machines and Free Weights Are Equally Good for Building MuscleFree Weights Are Equally Good for Building Muscle
After the eight-week training program, the researchers determined the strength and muscle gains of all participants. Muscle growth was determined in the thighs (quadriceps femoris muscle), chest (pectoralis major muscle), and abdominal muscles (rectus abdominis muscle). In addition, the maximum strength (1RM – i.e., the maximum weight with which a repetition can be performed) was tested and compared with the result of the test at the beginning of the study.
The surprising result: participants in both groups achieved comparable muscle gains. The increase in strength was also similar in both groups, regardless of whether the exercises were performed on free weights or machines.
Another interesting finding: even the perception of pain when the joints were stressed was almost identical in both groups. This contradicts the assumption that machine training is easier on the joints.
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Conclusion on Muscle Building
After evaluating the study, the researchers came to a clear conclusion: regardless of whether you train with free weights or on machines, the gains in muscle building and maximum strength are almost identical. Provided the training volume, intensity, and muscle strain are the same. Also important: the perceived load on the joints does not differ either. Of course, this only applies if the exercises are performed correctly. According to the study, those who pay attention to the correct execution of the exercises are free to decide whether they prefer to train with free weights or on machines. Both training methods are equally effective.
Tips for Better Muscle Growth
Obviously, it doesn’t make a big difference to muscle growth whether you train on machines or with free weights. However, building muscle is a complex matter. It is a combination of four important factors:
- nutrition
- training
- recovery
- consistent execution
Only if you pay attention to all four of these factors during strength training will you be rewarded with muscle growth.
The German original of this article was published in November 2025.
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