We're talking mobility again, this time the foam roller and LAX ball specifically. Are you doing it right?
1. Work upstream and downstream of the issue.
The site of the pain is often not the site of the issue. If your hamstrings are tight, try working on your glutes and calves. Or even work the same muscle that is giving you grief, but just a few cm above and below the pain.
You can't mobilise bone. I've spotted a few people trying to get into their necks, knees and hip bones. Also the shoulder blades. When on the foam roller, stick to the meat, you can cause some wicked bruising or pinching if you trap muscle between the roller and bone. LAX balls can get closer, and can be good for attacking connective tissue nice and close to the bony areas, but still be aware of going too far.
3. Too fast
I see this one a lot with LAX balls. You can't just flick it around your skin and expect results, you have to get some pressure on that thing! Slow down and increase the tension, and mindfully search out areas that need work.
4. Too slow
Don't fall asleep on that thing! A foam roll after exercise, is a great way to cool down, and doing it right before bed can help to stimulate the parasympathetic nervous system, which will make it easier to go to sleep.
But don't zone out completely, be engaged, don't just drape yourself over it and pass out. If you do that on a LAX ball, you might wake up with a nasty bruise.....
5. Rolling out a tight lower back
Your lower back is supposed to be tight (to a degree), in that the muscles in that area stabilise your body during movement. Trying to increase the range of motion in that area will just make those tight muscles lock down more. See #1 above and work on your thoracic and glutes/hamstrings/hip flexors instead.
And remember, post workout or rest days are best, before a workout you should stick to dynamic movements to get warm, and fully prepared for exercise.
3 x 6, building
7 DB Hang Power Cleans
7 DB Front Squats
50m Waiters Walk
AMRAP in 7mins
3 x 3, all heavy
7 Front Squat 60/40kg
7 Burpee Box Jumps 60/50cm
AMRAP in 7mins