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.
1 Upper body build-up exercises like crunches are also good for your hair. 2  You may be surprised but this is due to the fact that these are fairly intense workout routines which release a lot of sweat, and indirectly affect hair growth. Massaging the base of the neck and the shoulder, either by yourself or by getting some else to do it, has also been shown to help in re-growth of hair. 2  You can massage your left shoulder with your right hand and vice versa. 3  Upper body build-up exercises like crunches are also good for your hair.