molecule. 1  Chemistry, Physics. the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound. 2  Chemistry. a quantity of a substance, the weight of which, measured in any chosen unit, is numerically equal to the molecular weight; gram molecule.
When I do crunches my neck starts to tighten up and it makes me have to rest before doing another set of crunches.
I found the remedy for neck cracking is easy to fixâ¦. This video demonstrates how to end neck grinding and end neck clicking from home: A few observations and warnings: 1  Move soft and slow when trying these neck exercises for the first time.