
If you felt a stretch with that test, you should work to improve hip extension tightness. Performing the kneeling hip flexor stretch, which is a similar position to the test just described minus holding a stick along your back, is a good way to help lengthen and stretch the hip flexor. Some of you might be thinking, I do that stretch all of the time, and I still have tight hip flexors. Many of us do not hold our stretches long enough to allow them to actually achieve tissue lengthening. The old rule of thumb is to hold a stretch for 20 – 30 seconds and repeat 2 – 3 times. This might be ok for muscles that are not too short that you are just looking to relax them and return them to normal length after a workout. However, current research is showing that in order to lengthen tissue that is too short, the stretch must be held for 3 – 5 minutes.
http://www.fleetfeethartford.com/sports-medicine-corner/hip-extension