1- what is the range of ck for 17 year old male swimmer after a workout? 2- what happens if it was high, or low?

See answer : Normal reference ranges for serum ck: 55 to 170 iu/l for males. Although exercise is known to elevate ck, it produces a wide range of levels, based on many factors/variables. Higher-intensity, longer-duration, and weight-bearing exercise can raise ck levels 10-20x. Nonweight-bearing exercises and exercise involving no or minimal eccentric contractions, such as swimming cause only nominal increases.

Not specific: Working out will not always raise ck, it depends on impact, intensity, duration, resistance, general conditioning, other medical conditions, etc. Low #s are never a concern, there is no "minimum" requirement of ck to have. We start to worry when it hits 4 digits (1000+), and hydrate aggressively to keep it away from 5 figures, (10k+), where kidney damage is prone to occur. Few hundred is ok.