Reddit mentions of Stretching & Flexibility, 2nd edition

Kit Laughlin has some amazing material on this that goes into much more detail than most stretching programs. His basic approach is provide stretches not just for the hamstrings, but for all of the muscles which might limit your forward bend - so you stretch your calves, your piriformis (muscle on the side of your thigh), and of course your hamstrings.

I'd highly recommend either buying his book, or his hamstring-specific video program - I own both, and they're really good. The video series has over an hour of different hamstring-related stretches that you can go through to help find your tight points.

If you just want some quick stretches without buying any of the material, I'd try doing:

• This calf stretch
  
• This piriformis stretch
  
• This hamstring stretch
  
  Edit: Another good resource is Antranik's Toe Touching routine, which is probably a bit easier to approach for beginners than Kit Laughlin's stuff, and free to boot.

Bosu -- you can get them inexpensively at stores like Academy. I have the "mini" size one. I use it for several things: (1) using interval timer, stand on one foot on the bosu for 3 1-minute sets for each leg, (2) when you get good at that, do one-leg squats on the bosu, (3) flip it over (flat side up) and do normal squats while holding extra weight as needed. You'll find that you'll wiggle all over the place, and maybe fall off sometimes, until you get good. Just standing one-legged on the bosu will strengthen your foot, ankle, calves, knees, and hip, and especially in all the little micro-adjustment places that you need for stability.

You can do the same thing with a sissel.

Rubber bands: put band around your ankles and do side-shuffles and walk forward/backwards (move like a speed skater). Put them around your knees and do clamshells. Anchor a band in a door, stand on one foot, holding the free end of the band at arm's length and rotate your upper body against the tension of the band. Think wood chop exercise but standing on one foot so you put some beneficial torque on the knee and test its stability.

Movement exercises: sit on the floor (I have smooth wood floors) like you're in open guard, stretch your feet out in front of you, anchor your heels, and pull yourself forward; think like a butt-scoot, but using nothing but your glutes, hams, and calves. A bunch of normal calisthenics that work the leg chain (leg lifts, scissors, crazy legs, etc.). Lots of normal BJJ warmups are probably really good stability workouts.

Stretching: every leg stretch you can find. I found this book from the flexibility subreddit, and it's been amazing.

I'm really not sure where to find this stuff all put together, it's what I learned from my PT guys. I do this stuff about three times a week. Bosu every time, the other exercises I kind of mix in so I get to all of them once or twice a week.

Protection: I do wear knee braces, with the little silicone donuts in them. It helps a lot with impacts. Also keeps you thinking about knees and being careful and healthy.

I was referring to this video series, which is unsurpassed to my knowledge. He has Pancake, Squat, Shoulder, Pike and Bridge.

He also has a book but it's older content.