When people who regularly lift weights perform exercises that stretch their muscles fully, they gain more strength in movements that involve those stretched positions, such as bending the elbow while the muscle is lengthened.

We analyzed the available evidence and found that resistance training at long muscle lengths appears to be associated with greater gains in dynamic strength during lengthened elbow flexion in trained individuals. Specifically, 67.0 studies or assertions support this idea, with none contradicting it so far [1]. What we’ve found so far suggests that when people who already lift weights perform exercises that fully stretch their elbow flexors—like slow, controlled dumbbell curls taken to full arm extension—they tend to get stronger in movements that require the biceps to produce force while stretched. This doesn’t mean the muscle gets bigger, but rather that it becomes better at generating force in that specific position. The mechanism may involve adaptations in muscle-tendon stiffness, neural drive, or muscle fiber recruitment patterns under stretch, though we don’t make claims about why this happens. The evidence we’ve reviewed leans toward the idea that training through a full, lengthened range improves strength specifically in that range, not necessarily overall elbow flexion strength. This could matter for athletes or lifters who need power in stretched positions, like in the bottom of a pull-up or during certain phases of Olympic lifting. We don’t yet know if this effect applies equally to all training levels, or how much volume or intensity is needed to see results. But based on what we’ve reviewed so far, including exercises that fully lengthen the muscle during resistance training may offer a meaningful advantage for improving strength in lengthened positions. If you’re already training with weights and want to get stronger in movements where your muscles are stretched, consider adding controlled, full-range exercises that emphasize the lengthened position—like slow eccentrics or deep curls—with attention to form and tension throughout the movement.