I am taking exercise physiology online right now at USSA (ussa.edu). They have two options:
CER 520, a continuing education class that awards CEU credits (continuing education units) instead of normal semester credit hours. Check with the school you're applying to before registering- not all schools will accept this course. Mine will, which is great because it's not a lot of work and only cost $150.
SER 520- The same content as CER 520 but it awards normal semester credit hours, and has a proctered midterm, final, etc. This course is accepted by most DPT programs.