I have both the NASM-CPT and the NSCA-CSCS certifications.
I draw from the CSCS a bit more in the development of program design for my clients and athletes, however for a general population, it is easier to explain the concepts of the NASM-CPT and philosophies.
Both are great certifications, but if you do not have a degree in the health sciences or a related field, it may be more fitting to begin with the NASM certification.
I've designed a good comparison of nationally recognized and accredited certifications at http://www.my-personal-trainer-school.com
I draw from the CSCS a bit more in the development of program design for my clients and athletes, however for a general population, it is easier to explain the concepts of the NASM-CPT and philosophies.
Both are great certifications, but if you do not have a degree in the health sciences or a related field, it may be more fitting to begin with the NASM certification.
I've designed a good comparison of nationally recognized and accredited certifications at http://www.my-personal-trainer-school.com