People who train with weights almost to failure for five weeks may gain slightly more strength in their knee extensors than those who stop earlier, but the difference is too small to be certain it's real.

We analyzed the available evidence on whether training to near failure increases knee extensor strength more than stopping earlier, and what we’ve found so far is limited but suggestive. One assertion, supported by 46.0 studies or data points, indicates that people who train with weights almost to failure for five weeks may gain slightly more strength in their knee extensors compared to those who stop earlier—but the difference is too small to be certain it’s real [1]. We don’t have any studies that contradict this, but the lack of clear, measurable benefit means we can’t say training to near failure reliably leads to greater gains. The term “knee extensors” refers to the muscles that straighten your knee—mainly the quadriceps—and strength here is often measured by how much force you can produce during movements like leg extensions or squats. The evidence doesn’t show a big or consistent advantage, even though near-failure training is commonly recommended. Because the difference in strength gains is described as “too small to be certain,” we can’t say one approach is clearly better than the other. It’s possible that training closer to failure offers a tiny edge, but it’s also possible that the observed effect is just noise or variation between individuals. Without stronger or more numerous studies showing a meaningful pattern, we can’t draw firm conclusions. For someone looking to build knee extensor strength, this means you might not need to push every set to the brink. Stopping a few reps short could work just as well, and may help you train more consistently over time without excessive fatigue or risk of injury.