Lengthening the muscle down the front of the leg is the most important leg stretch. If the thigh muscle is tight, it will tilt the pelvis forward and create a sway in the lower back.
A simple technique is The Two-Chair Method.
Arrange two chairs facing the same direction.
Place one foot on the chair behind
For balance, place your hands on the back rest of the chair in front.
This should be comfortable for your knee, hip, and lower back and minimum tension in the front of your leg. Adaptations for comfort may include a lower or higher chair behind.
The stretch is achieved by tilting the pelvis backward or flattening your tummy.
Tilt the pelvis until you feel a tension in the front of the leg – about 20% of your limit.
Hold the stretch for 20-30 seconds until it relaxes. You can repeat this 2-3 times per leg. If no lengthening happens you may be pushing too hard.
Important: This stretch should be pain-free.
Take care not to arch your back during this stretch.
If you have difficulty with this exercise, contact your osteopath.