There’s a blatant divide in most gyms. Like choosing the red pill or the blue bill in “The Matrix,” gym goers often feel like they have to choose one path: machines (selectorized equipment that uses cables or pulleys) or free weights (such as barbells and dumbbells). Gyms often go so far as to divide their floor space into two separate areas based on equipment, making the decision to use one or the other even more divisive.
There’s been constant debate over which is better and whether it matters, so let’s take a look at what the research says.
WHAT’S THE GOAL?
First, it’s important to understand strength training leads to highly specific results. The SAID principle, which stands for “Specific Adaptations to Imposed Demands.” means you get what you train for. To make sure we’re not comparing apples to oranges, we looked at research comparing machines and free weights for three specific fitness goals:
- Losing weight
- Building muscle
- Gaining strength
Not surprisingly, the research draws different conclusions based on different training goals.
IF YOUR GOAL IS WEIGHT LOSS
According to the Centers for Disease Control and Prevention, nearly 40% of American adults are obese, so it’s no wonder weight loss is the most popular reason people go to the gym. However, if you’re looking to lose 10 pounds or fit into a smaller pair of jeans, there’s no definitive answer to whether you should use free weights or machines. Both free weights and machines work for fat loss, so choose the one you’re most comfortable with and enjoy most.
Weight loss relies primarily on creating a caloric deficit, meaning you must burn more calories than you eat through a combination of nutrition and exercise. According to the American College of Sports Medicine, any physical activity, regardless of the nature of its equipment, is suitable for weight loss as long as it is paired with moderate diet restriction that creates a caloric deficit.
- Focus on nutrition first. Track your calories to ensure a caloric deficit.
- Perform 2–4 hours of exercise per week with a combination of strength training and cardio.
IF YOUR GOAL IS BUILDING MUSCLE
Lifting weights to build muscle (also known as hypertrophy) requires both progressive overload (i.e., increasing the weight, sets and reps over time) and the right intensity (i.e., doing enough weight and reps so the muscles experience the right amount of fatigue).
The most reliable way to make your muscles grow is to recruit as many muscle fibers as possible. According to the size principle, your body recruits more muscle fibers when an exercise is especially challenging, such as doing as many reps as possible in a given set and stopping just shy of failure (i.e., you can barely complete the final rep). This style of training is often easier and safer with machines. For example, it’s easier to approach muscular failure on a leg extension machine than on a barbell squat, simply because it’s easier to maintain proper form.
However, the research suggests machines and free weights result in a similar amount of hypertrophy as long as the sets and reps are appropriate. The ACSM recommends moderate loading (70–85% of your 1-rep max) for 1–3 sets of 8–12 reps regardless of equipment.
Anecdotally, bodybuilders have used a combination of free weights and machines for decades. Few people know more about building muscle than bodybuilders, and although it’s not terribly scientific, there’s wisdom to be gained from the fact that the world’s most muscular people use both machines and free weights.
- Pick the right weights, sets and reps. 1–3 sets of 8–12 reps with a moderately heavy weight works best.
- Use whatever equipment lets you approach muscular failure without sacrificing technique.
- If you want to gain muscle, eat a slight caloric surplus with enough protein to build muscle (about 1 gram per kilogram of bodyweight).
IF YOUR GOAL IS GAINING STRENGTH
If getting stronger is your goal, the choice to use machines or free weights depends on what specific exercises you want to improve. The SAID principle reigns supreme here because strength relies heavily on neurological adaptations, meaning your body and brain work together to get more efficient at performing whatever exercise you practice the most.
Research shows free-weight exercises like the bench press and squat require complex neural responses and are more difficult to learn than machine-based exercises. That said, if you want to get stronger in free weight lifts that are used in strength sports such as powerlifting and weightlifting, you must practice those exercises. Don’t expect to set the world record in the barbell squat by doing nothing but leg presses.
However, if you simply want to make your body stronger for everyday activities, such as carrying groceries on climbing stairs, research suggests free weights and machines lead to similar results.
- You get stronger at what you practice, so choose free weights or machines based on the specific exercise you want to improve.
- Free-weight exercises are harder to learn because they’re more neurologically demanding.
After combing through the research, it’s safe to say machines and free weights work well for weight loss, gaining muscle and increasing strength. Each goal has specific requirements that must be met:
- Losing weight: caloric deficit
- Building muscle: approach muscular failure and caloric surplus
- Gaining strength: neurological adaptation
Free weights and machines can help with all of these things. There’s also no research that suggests you can’t use both to help reach your goals. Blend the best of both worlds and pick the right tools for your fitness aspirations.