Sports Massage is a type massage therapy that is very similar to a deep tissue massage with specific work on problem areas for athletes and weekend warriors. There are many "modalities" or "types" of massage therapy theses days, and Sports Massage is also a term to help categorize who a massage therapist works on and which massage therapist a new client will search for.
The benefits of massage are still present in all massage modalities, just different "benefits" are noticed after certain massage styles. When seeking a Sports Massage, for example, you would be looking for pain relief and help getting back to participating fully in your sport.