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.
How do I get rid of a knot in my neck. 1  Determine your trigger points by pressing down on the sore area and where the muscle is firm and dense will be a trigger point. 2  Massage the trigger points to relax the muscle fibers. 3  Move your arms.  Consider your stress level.