Starting position: Begin with your feet shoulder width apart and keep your legs slightly bent. Do not stand with your knees in a locked position. Pull your shoulders back in order to have a proper back arch.
Lunge position: When you lunge forward make sure to maintain the same back position that you had in the starting position. Do not allow your shoulders to roll forward. Also, make sure to pay attention to the placement of your front foot. Your front foot needs to be flat on the floor and in line with your knee. If you do not lunge far enough forward your knee will go past your front foot and put excessive pressure on the knee.
Return position: Returning to the starting lunge position should be done in one step backwards. If you find yourself taking more than one step backward then you are probably using too much weight or have lunged too far forward. Make sure to maintain the proper back position when returning to the starting position.
If you have difficulty returning to the starting position in one step when performing a body weight lunge, or experience knee pain when pushing back, then perform the split-squat instead.
1. Basic Lunge

2. Angled Lunge