As you struggle through your third set of crunches at the gym, one motivator might be the promise of six-pack abs. But for some people, this may not be physically possible — not because they aren't ...

Defined, toned abs — commonly called a six-pack — are an often sought-after goal in the gym. But not all toned abs look the same. Some people sport a four-pack, while others may have an eight-pack.