The Claim

In untrained young adults, performing barbell squats with a 4-second eccentric phase for 7 weeks results in a greater increase in one-repetition maximum strength (effect size = 1.60) compared to a 1-second eccentric phase (effect size = 0.99), with a statistically significant between-group difference (p < 0.05).

Source: The effects of eccentric phase tempo in squats on hypertrophy, strength, and contractile properties of the quadriceps femoris muscle

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

Untrained young adults who perform barbell squats with a 4-second lowering phase for 7 weeks gain more strength in a one-repetition maximum test than those who use a 1-second lowering phase.

See the scientific wording

In untrained young adults, performing barbell squats with a 4-second eccentric phase for 7 weeks results in a greater increase in one-repetition maximum strength (effect size = 1.60) compared to a 1-second eccentric phase (effect size = 0.99), with a statistically significant between-group difference (p < 0.05), suggesting slower eccentric tempo may enhance strength gains in compound lower-body movements.

Why this might work

Lowering a heavy weight slowly stretches muscle fibers for a longer time, causing the endurance-oriented muscle fibers to grow bigger. These bigger fibers produce more force and work more efficiently during maximum efforts, making it easier to lift heavier weights.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: The effects of eccentric phase tempo in squats on hypertrophy, strength, and contractile properties of the quadriceps femoris muscle

    People who slowly lowered the barbell during squats for 7 weeks got much stronger than those who lowered it quickly — the study proved it with numbers.

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

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