An amfetamine is an alternative term for an amphetamine.
Exercise - Sporting is good for health in overall, and it will also increase your metabolism because your body is in a more energy consuming state. The more intensive the better usually. Caffeine, tobacco, cannabis, cocaine, amfetamine - I don't know the exact mechanics but it has been my understanding that these substances all increase metabolism.
Adderall is a mixture of racemic amfetamine and dexamfetamine salts (4 specifically) that is considered water soluble (as opposed to lipid soluble), therefore it is not slowly eliminated from the body like certain benzodiazepines and THC. Generally it will not be detected after 48-72 hours depending on metabolism, kidney function, weight, etc. Sometimes it will not be detected after 24 hours (depending on the cutoff levels of the test) and sometimes only a few hours (this is not typical though). I take drug tests for a treatment program I'm participating in, and I take Dexedrine as prescribed, but several hours after taking it that same day, I went to my monthly buprenorphine doctor. We followed the same protocols (drug test, vitals, etc.) and when I certified my urine sample had not been tampered with, rigged, etc. I noticed it only detected the buprenorphine and benzodiazepines. So really, it goes to show you the accuracy of these tests and they can vary wildly.