The Claim

In moderately resistance-trained adults, machine-based exercises (hack squat, chest press) produce greater strength gains than free-weight compound lifts (squat, bench press) over a nine-week training period, regardless of training frequency, with exercise familiarity being a stronger determinant of strength adaptation than movement complexity.

Source: Equal-Volume Strength Training With Different Training Frequencies Induces Similar Muscle Hypertrophy and Strength Improvement in Trained Participants

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
68score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Cause and effect
1 study reviewed
In plain English

Among adults with moderate resistance training experience, using weight machines leads to greater increases in strength than using free weights over nine weeks, regardless of how often they train, because familiarity with the movement matters more than how complex the movement is.

See the scientific wording

In moderately resistance-trained adults, strength gains are greater in machine-based exercises (hack squat, chest press) than in free-weight compound lifts (squat, bench press) over nine weeks, regardless of training frequency, suggesting exercise familiarity may be a stronger determinant of strength adaptation than movement complexity.

Why this might work

When a person repeatedly uses a machine-based exercise, their brain and nerves learn the exact path and timing needed to move the weight, making the movement smoother and more powerful. This allows more muscle fibers to activate with less effort, leading to faster strength gains compared to free-weight exercises that require more coordination and balance.

Supported mechanismbased on 1 study

What the research says

1 study
  1. Study: Equal-Volume Strength Training With Different Training Frequencies Induces Similar Muscle Hypertrophy and Strength Improvement in Trained Participants

    People who already lift weights got stronger faster on machines like the hack squat and chest press than on free weights like squats and bench presses—even when they trained the same amount—because they were more used to the machines. It’s not about how hard the exercise is, but how familiar you are with it.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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