steroids
to improve their skills in the particular sport
People who do not use drugs are not at risk for legal penalties related to the use of illegal drugs.
It all depends on the sport. Different sports have different rules and regulations involving drugs (which are illegal and legal). If the drug happens to be illegal in the sport, disciplinary action will be taken and suspension will probably be the outcome.
Nothing....
It depends if it is a legal or an illegal drug. Illegal drugs such as heroine, drugs that hallucinate you are bad for sports. Steroids counts as cheating, and could mean a disqualification.
Yes, just like in any sport, there are soccer players that take drugs, both legal and illegal ones.
I'm Pretty Sure the Buddhists use Cannabis, or other "non legal" drugs in religious ceremonies, or to promote Meditation. Much the same as some American Indian tribes use Peyote.
legal drugs
Licit drugs are drugs that are legal.
steroids
Yes, you can get diseases by smoking legal drugs.
Drugs slower the nervous system.