Sometimes when your calcium/magnesium ratio is off, you can get twitching. I get one in my diaphram that feels like a fish flopping in my chest. If you are low in calcium intake, or very low in magnesium, the muscles do a dance of sorts. So you could try to balance that out.
(February 2017) A concrete slab is a common structural element of modern buildings. Horizontal slabs of steel reinforced concrete, typically between 4 and 20 inches (100 and 500 millimeters) thick, are most often used to construct floors and ceilings, while thinner slabs are also used for exterior paving.
My back ground is in Heavy Construction. We use the term Mud Slab or Mud Mat to describe a concrete slab that is poured on the ground. This slab allows you to have a solid area from which to tie your forms down too. It also allows you to keep you rebar and formwork clean and out of the mud.