AFAA stands for Aerobics and Fitness Association of America. AFAA personal trainer certification is a fast way to get certification, and the entire certification process can be done completely online.
The National Council on Strength and Fitness (NCSF) is an agency accredited through the National Commission for Certifying Agencies (NCCA). They offer certifications for personal trainers.
NSCA stands for the National Strength and Conditioning Association. This organization has many certifications, but the most popular is the Personal Trainer Certification. This is an entry level certification that can lead holders down the path to a career in the personal training field.