At last my foam roller arrived. Not bothering to read the booklet I jumped right in. Worked well too. I now have a pulled hamstring, a tight left IT band, a bruised left buttock and to cap it all off, I run 15 degrees to the left and I don't know why! That roller must be 20cm in diameter and at my age there needed to be some kind of user health warning. I FELL into positions I hadn't for 20 years. Off to give it another go now ... cautiously.