Let's say someone with below-average flexibility/mobility wanted to improve said areas for a specific sport (in this case, grappling/BJJ). What would you suggest to that person so that he was able to reach those goals?
Do some ROM/Dynamic stretching as your warm up before you grapple. After your session, do some static stretching. If someone can assist you, PNF stretching is great.
Would it be wise to devote an entire day to stretching?
Just taking a solid 30 minutes to work on all areas. The main areas that need the most work are hip flexor and hamstrings.
I've mostly been a post-workout, static-stretch type of guy. I do stretch before grappling, but nothing to strenuous. So, any new ideas are welcome as I really need to find ways to limber up.
I basically use a modified westside template, 3 days a week. I always do mobility work prior to the lifting session. Then on my "off" day, I will usually do mobility circuits non stop, trying to induce a sweat and also getting more mobile. Also, I stretch after each workout, and hit some tight spots prior to going to bed. It seems to have help.
Before bed, I have found that the stretching helps me relax and fall asleep easier. Try and stretch a little bit throughout the day. So after being awake for a few hours, hit about 5 minutes of stretching. Also, don't neglect foam roller work. Some of that hamstring tightness may be a tissue quality issue, I know mine was.
I'm relatively new to powerlifting, but just wanted to say that the format I have found most useful for flex/mob is definitely exactly the same as shadyniner's. Keeping mobile throughout the day and knowing specifically how to work the areas you are tightest (i.e. hip flexors and hamstrings) can be very helpful.
One pretty all inclusive resource on how and why to stretch for the right kind of flex/mob is Magnificent Mobility (DVD sold on this site). Also, I second the nod to foam roller work. It's kind of indispensable. Get the black one at elitefts.com. SO much better than the red or white ones.
What has worked for me is as above, working some stretches in throughout the day.
Then, each night (after a shower, or after my prehab work for my shoulders) I do a full, static stretching routine.
It also has helped me to get in dynamic motions that move the joints full their full ROM and a little beyond. If that makes any sense.
I'll take the obvious answer and suggest that you invest in the Magnificent Mobility dvd if you haven't already (but if you already have it, then you just need to review it and put it into action.) Cressey and Robertson did a seriously great job putting that together. They showed 30+ movements of varying difficulty and I've made four of them staples in my warm-ups every session. Night and day difference.
If it's a weakpoint, then yeah, I'd say it deserves some specific, dedicated attention. If you have a partner, you can get even more funky with some PNF/contract-relax stretching. But even if you're solo, there's a bunch you can do with a little planning. Just remember that if you're doing a stretching-only session, you still want a decent warm-up beforehand.
Fixing the hip flexors and getting them nice and mobile is going to make a world of difference. I like all sorts of lunge-position variations to target the area, but I'll also sometimes use a back kick/reverse leg swing-type of movement for a more dynamic drill.
I've always liked static stretching as a "cooldown" and to help ward off soreness post-weight training, but it's not the best for flexibility gains. That's going to be more a contract-relax/PNF type or something more dynamic.
Also, I just thought I'd add Alwyn Cosgrove's take on stretching, from his book "The Secrets of Martial Arts Conditioning":
So, um, yeah.
Thanks for all the tips, guys. As soon as I get over this sinus infection, I plan to start incoporating more stretching into my routine.