When I warm up, I start by rolling my neck clockwise and then anti-clockwise in circles. I then do the same with my shoulders, at first with my arm outstretched and then, faster, with my arm bent at the elbow. I rotate my hips, first with my knees held straight, and then with knees bent. I hold my body straight, dropping my head and chest first to one side and then another. To loosen my legs, I kick up and out from my heels. I rotate my ankle in circles. I hold my legs apart and drop my hand towards my toes. I stand tall pointing my toes high.
From an assistant in a runners’ shop I once learned to hook one leg in front of another, bend down at the waist, and lift my arms above my head. This unnatural movement is supposed to protect the cartilage on the outside of my knee.
I have also picked up a series of stretches based, albeit very loosely, on a tai chi class I once took, more than ten years ago. They do my body little good, I suspect, but at least in controlling my breathing I let my chest relax.