The Claim
In untrained young adults, performing barbell squats with a 4-second eccentric phase for 7 weeks increases time under tension by nearly double compared to a 1-second eccentric phase while reducing total training volume.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
In untrained young adults, using a 4-second lowering phase during barbell squats for 7 weeks doubles the time under tension compared to a 1-second lowering phase, while reducing the total amount of work performed.
See the scientific wording
In untrained young adults, performing barbell squats with a 4-second eccentric phase for 7 weeks increases time under tension by nearly double compared to a 1-second eccentric phase, while reducing total training volume, indicating a trade-off between mechanical load and duration.
When the lowering phase of a squat is slowed to four seconds, the muscles stay under strain longer, which activates more slow-twitch muscle fibers. These fibers grow larger and change their contraction speed, making the muscle thicker and slower to contract. At the same time, the repeated stretching of the muscle during the lowering phase causes structural changes that make the muscle stiffer and less likely to bulge outward when it contracts.
What the research says
1 studyThe study found that slowing down the lowering part of squats from 1 second to 4 seconds doubled the time your muscles are under strain, which is true — but it didn’t reduce the total amount of work done, as the claim says. Both groups did the same number of sets and lifts.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.