The short answer is YES – if done correctly for this purpose. Muscle fibers increase in size primarily from mechanical tension. This tension can come from force production where a muscle is producing force such as performing a resistance training exercise or from passive tension that occurs when stretching the structural elements of the muscle fiber itself.
To make things even more interesting muscle growth from mechanical tension from these two different methods is additive – meaning that when a muscle produces tension and is stretched at the same time more growth is triggered than from just producing tension or just stretching.
So the very best results come from making sure we use a full range of motion when performing resistance training and emphasize loading the target muscle at longer muscle lengths.
For example a review of 26 studies found that isometric exercises done in a position where our muscles are elongated (like the bottom of a bicep curl or the bottom position of a dumbbell fly) stimulate nearly 3 times as much muscle growth!
How to Incorporate Stretching Into a Muscle Building Routine
Incorporating stretching into your resistance training is actually pretty simple – choose exercises that challenge your muscle in a deep stretch position at the bottom of the lift and keep constant tension on the target muscle throughout the range of motion – including lowering slowly and smoothly. This means never unloading like resting a bar on your chest when doing a bench press.
Make sure to fully stretch the target muscle at the bottom of the movement – the key is challenging our muscles in that stretched position!