Most people think a lunge is an upright movement with the torso perpendicular to the ground throughout. But that's flawed mechanics. Maintaining a forward torso lean onto the heel of the front leg is essential.
The forward lean ensures the hips are pushed back posteriorly and actively engaged throughout the exercise. A good lunge involves solid hip hinge mechanics. An upright torso places greater stress on the knees and low back while minimizing stress to the glutes and upper thighs – not what you want.
2 – Move Straight Up and Down
When doing a stationary lunge, the torso should move straight up and down while keeping the forward lean. Any horizontal displacement of the torso indicates faulty hip mechanics and lack of spinal rigidity.
I've titled this article TNT (Tips-n-Tricks) for a very good reason. Many times it's the small things that make the biggest difference. Usually when reading a new book or article you walk away with one good idea. This one idea could've been presented in a paragraph or two. So I got to thinking, why not just provide all those great ideas in a format that cuts out the BS? What you're left with is pure TNT, the stuff great explosions are made of.