What is stretching?
It happens when we first wake up the in morning, as we reach our arms out to the world. It happens every time you take a step. Some muscles contract and others stretch to allow motion to happen. Within the fitness world, stretching generally refers to grabbing onto one of your limbs and pulling on it until you make a funny face or sound. This is termed, "passive stretching". Against your body's will, you are inducing what seems to be a method in which to lengthen your body parts. Now, does that really make sense? I mean, think about it... so if you really do succeed in lengthening out those muscles, then what happens to your skin? And your blood vessels? Nerves? Get back to me on that...
Give this a Try
Without getting into a heated debate here, let me simply propose "Active Stretching". This requires more work on your part, but remains in control by your motor system or central nervous system. When you actively contract a certain group of muscles, the opposing group generally has to relax or stretch to allow the motion.
TRY THIS! Lie on your back and instead of grabbing your leg and forcing into into your stomach, actively contract all of the muscles on the front of your leg (quadriceps, hip flexors) to lift your leg up toward the ceiling. You can even contract your abdominal muscles slightly to cause a posterior pelvic tilt and enhance the sensation. Are your hamstrings (back of thigh) stretching? They should be! If they do not feel a stretch, then it could be that they are already plenty flexible!
I personally prefer this because you get "more for your money" in that you are strenghtening and streching at the same time. Your central nervouse system is in control of how fat to take that stretch and everybody is happy (even me).
Flexibility
This brings me to my final point. How do we decide what is and isn't flexible? If every time you step or move, your body creates resistance to the point of discomfort than you have my full attention, especially if you are fairly sedentary or have a desk related job. However, if your body feels generally good in normal daily movement, then let it go! Of course when you grab your leg and pull it towards your head as far as you can, it will feel tight! At some point, the range of motion has to end and your nervous system will send a signal in some form or another: sharp pain, tightness, popping noise, etc.
Take this message home
Roll your shoulders, rotate your spine a few times, reach for your toes and reach for the sky. Keep your stretching simple and active. The body likes to move, it doesn't like to be forced. Be gentle with yourself and send me a message if you have more questions about this topic.