Free weights vs machines for muscle growth: what the research shows

For muscle growth, free weights, machines and cables give about the same result when your sets are hard and the weight keeps going up. Strength gains stay closest to the tool you trained with. So pick a few free-weight main lifts for the week and fill the rest with machines and cables.

Below you get the research in plain numbers, what it leaves open, a mixed week you can run, and what to do when the rack is taken.

Do free weights build more muscle than machines?

No. In the studies we have, both build about the same muscle.

Hypertrophy means muscle growth. Haugen and colleagues (2023) pooled 13 studies comparing free-weight training with machine training. In the studies that measured hypertrophy, they found no difference between the 2.

A single trial shows the same thing up close. Schwanbeck, Chilibeck and colleagues (2020) trained 46 adults, 26 women and 20 men, for 8 weeks. One group used free weights and the other used machines. Biceps and quad muscle thickness rose by similar amounts in both groups.

Be honest about the limits. The studies are small and short. Most last 6 to 12 weeks, and few include trained lifters. Nobody has followed experienced lifters on machines only for a year or more.

What does drive growth is clear enough. Hard sets are working sets that end within a few reps of failure, the point where you cannot do another clean rep. Take those sets with a weight that climbs over time. The tool matters less than either of those 2 things.

Are cables as good as dumbbells for growth?

For the side delts, yes. That is the one muscle with a direct test.

Larsen and colleagues (2025) ran a trial in trained men and women. Each person did cable lateral raises with one arm and dumbbell lateral raises with the other. Side delt thickness grew by similar amounts with both.

Cables do change one thing. The cable pulls through the whole rep, so the hardest point of the lift moves. A dumbbell raise is hardest near the top. A cable raise keeps tension near the bottom too.

One trial on one muscle cannot prove that this means more growth. No study has compared cable and dumbbell versions for most other muscles. Treat cables as an equal tool, not a better one.

That makes the choice practical. The dumbbell rack is crowded and the cable stack is free? Use the cable.

So why does strength depend on the equipment?

Because you get better at the exact lift you practise.

In the Haugen meta-analysis, free-weight strength tests improved more with free-weight training. Machine strength tests tended to improve more with machine training. Muscle grew about the same either way, but the skill did not transfer fully.

A free weight asks you to balance the bar, groove the path and brace. A machine does the balancing for you. Machines differ from gym to gym and do not teach you to balance a free weight.

So match the tool to the goal. If you want a bigger squat or bench, squat and bench. If you only want bigger legs, the leg press does the job.

When is each one the better pick?

Each tool has jobs it does better. None of them is the default for everything.

Free weights suit these cases:

• Main lifts: the ones you want to get stronger at, such as the squat, bench press and deadlift.
• A home gym: a barbell or a pair of dumbbells covers most of the body.
• A crowded gym: any free bench and a pair of dumbbells will do.

Machines suit these cases:

• New lifters: the fixed path lets you work hard before your technique is solid.
• Training alone: you can take a set close to failure without a spotter.
• Balance or grip limits: on a machine, balance is not your limit.

Cables suit these cases:

• Isolation work: lateral raises, triceps pushdowns, curls.
• Awkward angles: positions that dumbbells load poorly.
• Small jumps: many stacks move in smaller steps than the next dumbbell up.

There is one honest trade-off. Machine starting weights and weight stacks differ between gyms. A 60 kg chest press in one gym is not 60 kg in the next. Your machine numbers do not carry over when you change gyms.

How do you mix them in one week?

Put free weights first and machines and cables after. The rule is simple: 1 or 2 free-weight main lifts per session, then 2 to 4 machine or cable lifts.

Here is the first half of a 4-day upper/lower week. Train Upper A on Monday and Lower A on Tuesday. Upper B and Lower B follow on Thursday and Friday.

Build Upper B and Lower B the same way. Open with different free-weight main lifts, for example the overhead press and the Romanian deadlift. Then fill the rest with machines and cables.

Count hard sets per muscle across all 3 tools. A set on the cable counts the same as a set with dumbbells. Our post on how many sets and reps build muscle gives about 10 to 20 hard sets per muscle a week. Warm-up sets do not count.

Use double progression on every tool. Double progression means you stay at one weight until you hit the top of the rep range on every set. Then you add the smallest step and work back up from the bottom of the range. Leg press 120 kg for 3 sets of 12, and next session it is 125 kg for 3 sets of 10. Our progressive overload guide walks through it.

Weight stacks jump in fixed steps. Sometimes the next pin is too heavy for your reps. When the step is too big, add reps first and move the pin later.

Stronger by Science's review of the meta-analysis makes the same point: free weights and machines can work together in one muscle-building program.

What should you do when the rack is taken or a joint hurts?

Pick the same movement on another tool, and keep the set count.

The bench is taken? Do a machine chest press. A dumbbell row is not possible? Do a seated cable row. The muscle gets the same hard sets, so your week's set count stays the same.

Pain is a different case. Your shoulder hurts on the bench? Swap the exercise for one that spares the joint, such as a machine press or a cable fly. Do not push through it. Diagnosis and treatment belong to a physio or a doctor.

Log the swap under its real name. A machine chest press is not a bench press. Next session, you want the weight to compare like with like.

How does Trackist handle free weights, machines and cables?

Trackist builds the plan from the equipment you have.

Equipment is part of your training profile. You tick what you have, such as a barbell, dumbbells, machines or cables. The coach writes a plan of 4 to 12 weeks around your gym and your week. The plan and the swap list are filtered to that equipment. Ticking machines and cables only makes every exercise one you can do on them.

The exercise library holds 240 movements. Every strength exercise has written form cues, the muscles worked and a muscle map. There are no exercise videos.

Trackist suggests the next weight from the sets you log. When you hit the top of the rep range on every set, it adds a step that fits the tool: 2.5 kg on a barbell, 2 kg on dumbbells, 5 kg on a machine or cable.

The rack is taken? You can swap an exercise for today or for the rest of the plan. When something hurts, you name the exercise, the joint and how bad it is from 1 to 5. The coach swaps in one that spares the joint and usually trains the same muscle. Trackist changes the exercise. It does not treat the injury.

Trackist has no gym profiles. If you train in 2 gyms, the second gym's equipment is not stored separately.

Log your next session in Trackist. Trackist writes a plan around your week and your gym, and suggests your next weight from the sets you logged.

Putting it together

For growth, the tool matters little. Hard sets close to failure and a weight that climbs do the work, on a barbell, a machine or a cable.

For strength, train the lift you want to get stronger at. A bigger leg press does not mean a bigger squat.

In the week, put 1 or 2 free-weight main lifts first. Fill the rest with machines and cables, count every hard set, and run every tool on double progression. Want a full week built this way? Start with our hypertrophy workout plan.