My first go-to stretch for opening up our hips and improving our mobility prior to squatting is called the “World’s Greatest Stretch.” This stretch has 4 parts to it.
First, start by assuming a deep lunge position with your left leg forward. Squeeze your glutes & straighten out your back leg. This movement should cause a stretch to be felt in the hips.
Second, drop your left elbow to the ground. Hold for 5 seconds. Next, use your elbow or hand to drive your left knee out to the side. Make sure to keep your foot firmly planted on the ground.
Finally, rotate the entire upper body up and to the left, ending with the left arm in the air. This last movement helps address the mobility of the thoracic (mid-spine) that is
also prone to stiffness.