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.
Best Answer: Its the lower abs also called the pouch I think. Try this out Do Crunches. Lie on the floor (with or without a mat). Cross your arms in front of your chest.(Donot place both hands behind your head.he most important part of the crunch is the initial flexing of your abs as you lift your shoulders off of the floor. As soon as you begin lifting off the floor exhale through your mouth, ending with a gasp once your shoulders are off the floor.