There are two types of rollers: full round and half round rollers. There are a range of stretches you can do in different positions from lying on them to standing. Using rollers challenges you to maintain core stability while doing various movements.
I recently tried one of the exercises. It seemed an easy exercise: lie on a half roller and raise your arms, one at a time over your head letting the arm should rest on the floor behind you. The challenge, lying on the roller, is to keep your balance while doing the movements. Sounds fairly simple.
The first time I did the move, I did it fairly quickly. Easy.
Then I repeated the movement this time but slower. Paying attention to what I was doing, I realised that there was a difference in how easy the move was between the right and left sides! Moving the right arm was easy and the arm easily rested on the floor. Moving the left arm was a different matter. I could easily move the arm over the head but there was then a feeling that it should be on the floor and it wasn't! (That was actually quite an odd feeling - almost as if the floor had shifted!)
To get the left arm onto the floor, I had to make more of an effort and I could feel a stretch coming up the left side of my body. Hmm, my left side could do with more stretching.
Depending on how quickly you do something, there is a difference in what you notice. Doing a move slower revealed subtle differences in my arm movements that were not obvious when doing the movement quickly.
Take time to feel what you are doing whether it is stretching or doing a massage!
Speed really does matter!