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.
Slab-on-grade foundation. As the name suggests, a slab is a single layer of concrete, several inches thick. The slab is poured thicker at the edges, to form an integral footing; reinforcing rods strengthen the thickened edge. The slab normally rests on a bed of crushed gravel to improve drainage. Casting a wire mesh in the concrete reduces the chance of cracking. A slab on grade is suitable in areas where the ground doesn't freeze, but it can also be adapted with insulation to prevent it from being affected by the frost heaves. (see below) In summary: Slab on grade used in areas where ground does not freeze. The edges of the slab-on-grade are thicker than the interior of the slab. The slab-on-grade is monolithic (poured all at one time).