Thomas Hip Flexor Test: Sit at the edge of a raised surface (e.g. bed). Bring one leg up towards your chest, and begin to lie back on the bed, keeping the other leg passively hanging. Your hanging limb should be able to go down past the midline of your body with minimal resistance.
If it feels tight or doesn’t go past your midline then you may have restrictions in your quadriceps or hip flexors. Furthermore, if your leg shifts or rotates to the side then that could indicate restrictions in your IT Band. Either way, proceed with Hip Flexibility.
Prone Quad Test: On a raised surface, lie your body down with one leg on the table and the other off to the side. With a Resistance Belt looped around your foot, bring your foot towards your hips while keeping your body aligned. If you do not have a strap then you can use your hand. Ideally, your heel will hit your hips with minimal stretch in the quadriceps muscle (i.e. the thigh on the table).
If you cannot touch your heel to your hips with your knee bent then your IT Band and quads are restricted, so proceed with Quad/IT Band Flexibility.
Toe Extension Test: While sitting, bring your toe up toward your ankle. You should get at least 75 degrees of toe extension. This is measured from the midline of foot to the midline of toe.
If you are unable to achieve a 75-degree toe extension then you have foot restrictions, so continue with Foot Flexibility.