Upright Torso Lunge

There's absolutely nothing wrong with doing lunges with an upright torso position. In fact, if you're looking to focus more on the quadriceps, an upright torso position is absolutely in order. Taking a longer stride (with a vertical tibia) is a more hip oriented version of this exercise, whereas taking a shorter stride with a slightly angled tibia is a more knee (quad) oriented version. So, if you're really trying to hammer the quad, you'd combine an upright torso with a slightly reduced stance length that creates a tibia angle similar to the tibia angle involved in a standard back squat. That said, it's important for females to note that placing an emphasis on performing hamstring-oriented exercises, like leaning lunges and RDL lunges, can be especially helpful for them, since women are more quadriceps dominant than men, tend to have weaker hamstrings, and therefore may be more prone to knee injury. – Nick Tumminello