Flexibility and martial arts

Ballistic stretching is pretty standard isometric stretching like see in TommyK's post above but you bounce and bounce to stretch. In my opinion people who can't stand the enormous pain isometric stretching might cause use this instead because they only need to be in the pain zone for a short period of time. Can be effective but will most likely just cause from slight to vital injuries, even though you might not feel anything bad afterwards there is still a chance you have caused some trauma to your nerves, muscletissue or strings which might in the end hinder your flexibility.

Dynamic stretching is flexibility in motion, in other words it is just doing leg raises to all directions. This is a good way to increase flexibility but going beyond your determined passive flexibility is almost similar to ballistic stretching and can cause the same problems.

Passive stretching or isometric stretching is in my opinion the best and safest way to stretch. The only problem is that it is not for pussies, you have to be long periods of time in very uncomfortable stretches to increase your passive stretching level. I think the flexibility dynamic stretching provides is awesome but not enough, by isometric stretching you can stretch muscles which aren't affected by the dynamic leg raises.

In conclusion, I'd use dynamic stretching and isometric stretching. Always do the dynamic stretching first, you can do that like everyday multiple times. Isometric stretching you should do like training muscles, 3-5 sets with 30secs to 5mins stretchs, 1-3 times a week. No isometric stretching should also be done sore.

http://www.elitesoccerconditioning.com/Stretching-Flexibility/DynamicStretchingvsStaticStretching.htm

The article talks about dynamic stretching and a tad about ballistic stretching.   

Although this is a bit of an ad it might give you a hint about flexibility.
http://www.performbetter.com/webapp/wcs/stores/servlet/PBOnePieceView?storeId=10151&catalogId=10751&languageId=-1&pagename=133
I've been studying flexibility quite a bit recently and I would concern yourself first and foremost with any postural imbalances you have and aim to correct those through stretching. Stretching aimlessly or all of your muscles or without any plan is just as bad as lifting equally as haphazardly. Stretching is a tool, a vital tool, just like any other part of fitness. There are many modalities to stretching and many forms of stretching. I am considering writing a guide to all this, but I digress.

What I would recommend to you is that after finding out your imbalances and postural problems (lookup Neanderthal No More and read all of the posts, do all of the assessments, check out everything you can from Eric Cressey, Mike Robertson and Bill Hartman on the subject if you want to learn or know where to buy a quality product. All these guys are great) and figure out what it is you need to lengthen if anything. There's a big difference between short muscles and stiff muscles.
http://robertsontrainingsystems.blogspot.com/2008/10/bill-hartman-guest-blog-stiffness-vs.html
Now that you have that figured out, I'd recommend this for your flexibility program (you have a workout program or lifting program and that has goals. There should be 0 difference between this and your flexibility and mobility program. There's goals, there's work, there's purpose!):
1. Go to Mike Robertson's site and sign up for the newsletter, if you don't want the e-mails then right after you download the free SMR guide then get off the mailing list. Why download this?

Because foam rolling is a great way for $10 or maybe even less if you own a tennis ball, lacrosse ball or medicine ball already to improve muscle tone. I'm imagining you don't have $$$ for massage so this is as good as you're going to get. Get rolling and get flexible. The how, why and when is all written about in that guide.

2. Do dynamic stretches and mobility drills before every workout as part of/the meat of your warmup. If you learn your postural and muscular imbalances this would be a great time to do activation drills too. A reason many people are less flexible than they can be is because their imbalances put muscles in a state of constant tension.

3. Post workout do eccentric quasi isometrics.
http://www.t-nation.com/strength-training-topics/extreme-range-split-squat
They mention at the end how to do an EQI for your Hip flexors.
Mike Robertson talks here about how to incorporate EQI's and gives examples of one's for your chest and lats and it's overall a great article
http://articles.elitefts.com/articles/rehabilitation/did-you-know-youre-dysfunctional/

4. At night before bed or after a hot shower (or if you want to be the MAN both!) do your static stretching. That's 30-90 second holds (you can and in some cases it is appropriate to hold stretches for as long as 20 minutes but that is more advanced and I'm still researching that myself).

For ALL stretching keep in mind that you want to keep the stretch MILD. If you really stretch extremely there's the risk of injury, but even more likely is that you'll make yourself WORSE. Your body becomes more flexible as an adaption or less flexible as an adaption (or either as a reaction to acute stimulus). What do I mean? That because you sit for hours and hours a day your body decides it doesn't need as many sacromeres in your hip flexors and you become less flexible. These muscles shorten. The acute stimulus? If you stretch to a intense degree and especially if you do so in a state where you are not relaxed your body may interpret this as stretching to the point of injury and as a response TIGHTEN UP! That means everything would get much worse! So when you stretch you want to relax, breathe through your diaphragm and when you exhale fall deeper into the stretch. Focus on letting the muscle in stretch be free of tension. Make sure you're getting mobility FROM WHAT YOU ARE STRETCHING. Most people when stretching any part of their body, ANY part will get range through their lower back and not their hip flexors or hamstrings or anything else. Just like using momentum to get a weight up doesn't help...this sure won't help either.

Now to give you an idea of how often you need to stretch--if you lift weights and do a chest workout and lets say every set you do 2s up 2s down and you have 4 exercises for chest and each is 8  reps, 3 sets that comes to  6.4 minutes (if the math I just did really quickly is right) of time under tension for your chest. Now that means unless you stretch 6.4 minutes at least you're going to lose length of those muscles. That's just to MAINTAIN flexibility! So this is why stretching should be an integral and well thought out part of your program. I can talk to you endlessly about the benefits of stretching and the harmful effects it has as well but there's the idea.

Hope that helps, if you listen I know it will   !

Nice post Para.

In my opinion one should do many ways of flexibility(dynamic, isometric, static) but also not forget the second most important parts of flexibility: joints. Especially doing several numbers of exercises to your hip you can seriously open up your hip joints allowing you to perform much better and easier kicks. I've done this for a few times now and my body feel much better and healthier, I just love it when your bones start to pop and you notice "wtf, it's not tense anymore!".

It's called joint mobilization. Check it from youtube etc. The best video I found is unfortunately in Finnish only but the guy does this from his jaw to his ankles. Just set the volume zero and watch it carefully

Mobbaus 1/3