Dr. Jonathan Sum is the Director of USC Physical Therapy Associates on the Health Sciences Campus, the faculty practice for the USC Division of Biokinesiology and Physical Therapy. He specializes in treating patients with orthopedic disorders, sports related injuries, post-surgical rehabilitation, pain management, and musical performance related injuries. Dr. Sum is double board certified by the American Board of Physical Therapy Specialties, both as an Orthopedic Clinical Specialist, and a Sports Clinical Specialist. He is a member of the Orthopedic Section and the Sports Section of the American Physical Therapy Association. He is also a Certified Strength and Conditioning Specialist, and a member of the National Strength and Conditioning Association.

Dr. Sum is an Instructor of Clinical Physical Therapy in the USC Division of Biokinesiology and Physical Therapy. He teaches in the Doctor of Physical Therapy program where he coordinates the shoulder complex module for the patient management courses in the first year. He is also a faculty mentor in the Orthopedic Physical Therapy residency program and the Sports Physical Therapy residency program at USC. For the Keck School of Medicine of USC, Dr. Sum instructs the musculoskeletal examination labs for the Introduction to Clinical Medicine courses, and has guest lectured for the Thornton School of Music. He has also been a returning guest panelist for the Kinesiology Club.

Along with his clinical and academic pursuits, Dr. Sum has also been published in the International Journal of Sports Physical Therapy, and has been an invited speaker at several local, state, and national conferences. He has been involved with research studying the lumbar spine and the shoulder complex, as well as examining jazz guitarists. Dr. Sum also assists with pre-season physicals for the Los Angeles Angels of Anaheim professional baseball club during Cactus League Spring Training every year.