Why Are Lunges So Good At Building Muscle?
The following makes up the bulk of why lunges are such an excellent movement in the realm of muscle building.
There are three stages of muscle contraction: concentric; where we are lifting the weight, isometric; where we are holding the weight, and eccentric; when we are lowering the weight. We discuss all three in depth here, but the main takeaway is that the most effective stage to build muscle is the eccentric part where muscles get stretched and lengthened, NOT contracted. Why? Hypothesis around why this stage of the lift is so effective is generally centered around the fact that it causes the most muscle damage.
In the lunge, there is huge eccentric demand, and the likely reason that it causes an incredible amount of soreness at challenging loads. The reason why we are always telling you not to slam your knee on the lunge goes well beyond it being bad for your knee. When you slam your knee onto the ground, it means you are moving very fast and out of control, and the key to any good eccentric phase of a lift is slow and under control.
With your knee, think kiss, not slam. That’s right.
Whereas the squat is a bilateral movement, both legs moving at the same time lifting the same load, the lunge is a unilateral movement where only one leg is moving forward. This creates symmetry and balance with our muscular and physique development and evens out any asymmetry brought on by a stronger side dominance in bilateral movements.
Let’s not forget that a heavy barbell across our backs is always going to build muscle in our lats and shoulders. No matter the movement. Those muscles are responsible from keeping the stress off of our spine, so even if you think you aren’t targeting them, your CNS has them firing and that alone can be an effective muscle builder isometrically.
The lunge is a great movement to even out strength imbalances, actively enhance your functional strength, and build serious muscle in our glutes, quads, and hamstrings. Because of the upright position, there is very little shear force on the spine making it one of the better all around movements we can do for our fitness.