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.
What is the proper technique for an abdominal crunch? The proper technique for an abdominal crunch is to make sure that you isolate your abdominal area so that you do not use anything else such as your neck muscles, make sure thaâ¦t you only use the desired area which in this case is the abdominal area.