THE TYPICAL LUNGE
* The typical lunge taught is stepping forward, performing the lunge, then returning to the starting position.

* The problems with this "Typical Lunge" are that
1. The front leg is only working for a small part of the time. It's only working when it's in the lunge position. It's not doing anything during the stepping motion
2. There is no full hip extension
3. There's a sheering effect that occurs at the knee when pushing BACK to the starting position. This could possibly cause injuries to your knee joint.

THE WALKING LUNGE - a better alternative.
* When doing a walking lunge you move across the room, from lunge position to lunge position. This technique eliminates problems #2 & #3. It, however, does not address #1...the front leg is only working once it lands. There's too much time when the "working" leg isn't actually working.

THE REVERSE LUNGE - the best alternative
* The reverse lunge is really quite simple. The only difference is that instead of stepping forward we step BACK into a lunge. This easy adjustment has a lot of added benefits:
1. As soon as you start to step backward, your front leg which is your working leg is ACTUALLY WORKING through hip stabilization.
2. You can work ONE leg at a time. There is no need to alternate legs. I can easily do 12 lunges with my right leg in front then 12 lunges with my left leg in front. Alternating legs gives too much rest. You'll get better results if you don't alternate legs after every rep.
3. You don't need a big area to work in since you're just stepping back then returning to the starting position. You're not really moving anywhere.
4. You do get full hip extension when returning to the starting standing position.