The hip flexor (also known as the psoas muscle) is a muscle that runs from the thigh bone to the vertebrae in the low back.
Due to how much time we spend sitting, this muscle gets tight on a regular basis. I have talked about not stretching tight muscles before but in this case, the muscle may actually need to be stretched.
The problem arises from people butchering the movement. Instead of stretching the psoas, they are stressing other structures around the hip and low back.
The key to performing this movement correctly is the setup. If you set up properly, you have a chance. If you do not, you will feel stuff pulling but it is doubtful you will be stretching the hip flexor.
Check out the video below for tip to performing the stretch correctly.
This stretch can be done as a stand-alone movement or it could be done throughout the day to break up too much time in a seated position.
Hold the stretch for 20-30s on each side.