Jonathan C. Sum, PT, DPT, OCS, SCS

Associate Professor of Clinical Physical Therapy

Professional Interests

Dr. Jonathan C. Sum 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 American Academy of Sports Physical Therapy and the Academy of Orthopedic Physical Therapy of the American Physical Therapy Association. He is an active member of ASSET, the American Society of Shoulder and Elbow Therapists, and has served on the Executive Board of ASSET in various capacities.

Dr. Sum teaches throughout the Doctor of Physical Therapy curriculum, both in the residential and hybrid pathways. He serves as a faculty content expert for upper extremity, youth athletics and health systems. Dr. Sum is the director of the Upper Extremity Athlete Fellowship, which is the nation’s second university-based upper extremity PT fellowship to be affiliated with a professional baseball organization. He is also a clinical mentor in the Orthopedic Physical Therapy Residency program and the Sports Physical Therapy Residency program at USC. In the Sports Physical Therapy Residency program, he coordinates the overhead throwing curriculum. He has guest lectured for USC’s Keck School of Medicine and the USC Thornton School of Music, as well as co-directs a course in the master’s program in pain medicine program from the Keck School of Medicine and the USC Herman Ostrow School of Dentistry. Dr. Sum also assists with Minor League Baseball pre-season physicals during spring training every year.Along with his clinical and academic pursuits, Dr. Sum has also been published in several peer-reviewed journals and has been an invited speaker at local, state and national conferences. He is a clinical associate in the COOR Lab and has been involved with research examining the physical factors related to performance and recovery of the upper extremity in sports, physical factors related to shoulder disorders, sports recovery wear, testosterone supplemented ACL-deficient knees, body weight-assisted training following knee replacement, lumbar spine disc loading, lumbopelvic manipulation, and Achilles tendinopathy.

Education

  • Doctor of Physical Therapy, University of Southern California, 2005
  • Bachelor of Science, Kinesiology, University of Southern California, 2001

See Jonathan Sum’s curriculum vitae.

Peer-Reviewed Publications

  1. Michener LA, Barrack AJ, Liebeskind BY, Zerega RJ, Sum JC, Crotin RL, Plummer HA. Shoulder external and internal rotation strength profiles in professional baseball players: effects of player position and geographic origin. Int J Sports Phys Ther. 2021;16(4):1126-1134.
  2. Zipser MC, Plummer HA, Kindstrand N, Sum JC, Li B, Michener LA. Hip Abduction Strength: Relationship to Trunk and Lower Extremity Motion During A Single-Leg Step-Down Task in Professional Baseball Players. Int J Sports Phys Ther. 2021;16(2):342-349.
  3. Zipser MC, Sum JC, Wilcox A. Little leaguer’s shoulder. J Orthop Sports Phys Ther. 2018;48(1):51.
  4. Plummer, HA, Sum JC, Pozzi F, Varghese R, Michener LA. Observational Scapular Dyskinesis: known-groups validity in patients with and without shoulder pain. J Orthop Sports Phys Ther. 2017;47(8):530-7.
  5. Wu B, Lorenzana D, Badash I, Berger M, Lane C, Sum JC, Hatch GF, Schroeder ET. Perioperative testosterone supplementation increases lean mass in healthy men undergoing anterior cruciate ligament reconstruction: a randomized controlled trial. Orthop J Sports Med. 2017;5(8):1-9.
  6. Skinner C, Franklin S, Chang J, Sum J, Groshen S, Hatch G. Demographics, activity level, and shoulder health history of populations participating in CrossFit: a descriptive analysis. Austin J Orthopade & Rheumatol. 2017;4(2):1052.
  7. Tilson JK, Mickan S, R Howard, Sum JC, Zibell M, Cleary L, Mody B, Michener LA. Promoting physical therapists’ use of research evidence to inform clinical practice: part 3 – long term feasibility of the PEAK program. BMC Med Educ. 2016; 16(1):144.
  8. Cole S, Sanderson T, McNeill BT, Sum JC. A Proposal for Functional Screening of the Throwing Kinetic Chain in Baseball Pitchers to assess Shoulder and Elbow Injury Risk. Sport Exerc Med Open J. 2015;1(5):151-8.
  9. Riva SS, Sum JC, Hatch GF. Functional movement analysis in the differential diagnosis of a patient with a posterolateral corner knee injury. Sport Exerc Med Open J. 2015;1(2):47-53.
  10. Hawkins AP, Sum JC, Kirages D, Sigman E, Sahai-Srivastava S. Pelvic osteomyelitis presenting as groin and medial thigh pain: a resident’s case problem. J Orthop Sports Phys Ther. 2015;45(4):306-15.
  11. Wu B, Berger M, Sum JC, Hatch GF, Schroeder ET. Randomized control trial to evaluate the effects of acute testosterone administration in men on muscle mass, strength, and physical function following ACL reconstructive surgery: rationale, design, methods. BMC Surg. 2014;14(102).
  12. Tilson JK, Mickan S, Sum JC, Zibell M, Dylla JM, Howard R. Promoting physical therapists’ use of research evidence to inform clinical practice: part 2 – a mixed methods evaluation of the PEAK program. BMC Med Educ. 2014;14(1):126.
  13. Sum JC, Omid R. Superior labrum anterior to posterior tear. J Orthop Sports Phys Ther. 2012;42(12):1050.
  14. Sum JC, Hatch GF. Osteochondritis Dissecans. J Orthop Sports Phys Ther. 2011;41(10):797.
  15. Hensley CP, Sum J. Physical therapy intervention for a former powerlifter after arthroscopic microfracture procedure for grade IV glenohumeral chondral defects. Int J Sports Phys Ther. 2011 Mar;6(1):10-26.
  16. Popovich JM Jr, Sum JC, Poppert EM, Colletti PM, Kulig K. Axial loading of the lumbar spine in persons with acute low back pain: a kinematic analysis. Clinical Kinesiology: Journal of the American Kinesiotherapy Association, vol.59, no.1, 2005.

Research Publications / Presentations at Scientific Meetings (Abstracts)

  1. Barrack AJ, Michener LA, Liebeskind BY, Zerega RJ, Sum JC, Crotin RL, Plummer HA. Rotational Shoulder Strength Profiles In North And Latin American Professional Baseball Pitchers And Position Players. Annual Meeting, American College of Sports Medicine, Virtual, 2021.
  2. Stirling BD, Baek L, Sum JC, Michener LA, Barrack AJ, Tate AR. Shoulder Pain in Competitive Swimmers: A Multisite Survey Study. Platform Presentation, Combined Sections Meeting, American Physical Therapy Association, Virtual, 2021.
  3. Baek L, Stirling BD, Sum JC, Barrack AJ, Michener LA, Tate AR. US Swimmers’ Shoulder Pain and Coaches’ Experience, Education, and Views on Injury Prevention. Platform Presentation, Combined Sections Meeting, American Physical Therapy Association, Virtual, 2021.
  4. Sum JC, Omid R. Rehabilitation following arthroscopic superior capsule reconstruction. Platform Presentation, Annual Meeting, American Society of Shoulder and Elbow Therapists, Virtual Meeting, Oct. 2, 2020.
  5. Tate AR, Sum JC, Stirling B, Baek L, Michener LA, Barrack AJ. Multicenter survey investigating United States youth competitive swimmers’ shoulder pain disability and training, and their coaches’ experience, education and views on shoulder injury prevention. Platform Presentation, Annual Meeting, American Society of Shoulder and Elbow Therapists, Virtual Meeting, Oct. 2, 2020.
  6. Matsuno K, Dionio K, Seto E, Chavez A, Schroeder ET, Sum JC. Effects of Recovery Sleeves on Professional Basketball Players. Poster Presentation, USC Division of Biokinesiology and Physical Therapy Jacqueline Perry Research Day, Los Angeles, California, April 18, 2019.
  7. Stirling B, Sum JC, Knight T.  Effects of Incrediwear®. Recovery Leg Sleeves on Time-Loss for Major League Soccer Players. Poster Presentation, Combined Sections Meeting, American Physical Therapy Association, Washington D.C., Jan. 26, 2019.
  8. Zipser MC, Plummer H, Hostetter G, Li B, Sum JC, Michener LA. Hip abduction strength relationship to single-leg step down task in professional baseball players. Poster Presentation, Combined Sections Meeting, American Physical Therapy Association, Washington DC, Jan. 26, 2019.
  9. Pozzi F, Plummer H, Sum JC, McNeill BT, Chow K, Winstein CL, Michener LA. Functional recovery of patients with full thickness rotator cuff tears discharged from physical therapy. Poster Presentation, Combined Sections Meeting, American Physical Therapy Association, Washington D.C., Jan. 26, 2019.
  10. Stirling B, Sum JC, Knight T. Effects of Incrediwear. Recovery Leg Sleeves on Time-Loss for Major League Soccer Players. Poster Presentation, Annual Meeting, California Physical Therapy Association, Santa Clara, California, Sept. 22, 2018.
  11. Stirling B, Sum JC, Knight T. Effects of Incrediwear. Recovery Leg Sleeves on Time-Loss for Major League Soccer Players. Poster presentation, USC Division of Biokinesiology and Physical Therapy Jacqueline Perry Research Day, Los Angeles, California, April 10, 2018.
  12. Pozzi F, Plummer H, Sum JC, McNeill BT, Chow K, Itamura JM, Michener LA.  Feasibility and Efficacy of a Closed Chain Strengthening Protocol for Patients with Full Thickness Rotator Cuff Tears. Platform Presentation, Combined Sections Meeting, American Physical Therapy Association, New Orleans, Louisiana, Feb. 22, 2018.
  13. Sum JC. Rehabilitation following Superior Capsular Reconstruction. Session presentation, USC Shoulder Update 2018, USC Division of Biokinesiology and Physical Therapy, Los Angeles, California, Feb. 3, 2018.
  14. Sum JCEvaluation of the Overhead Athlete. Session presentation, USC Science of Throwing and Hitting, USC Division of Biokinesiology and Physical Therapy, Los Angeles, California, Feb. 2, 2018.
  15. McNeill BT, Sum JC, Pozzi F, Plummer H, Michener LA. Feasibility and Efficacy of a Closed Chain Strengthening Protocol for Patients with Full Thickness Rotator Cuff Tears. Platform Presentation, Annual Meeting, American Society of Shoulder and Elbow Therapists, New Orleans, Louisiana, Oct. 14, 2017.
  16. Stirling B, Sum JC, Ayoob K, Baek L, Bryant M, Chang J, Curran J, Hankard J, Weedman C, Yim C, Zeiger B. Prevalence of shoulder pain in United States youth competitive swimmers. Research Podium Presentation, Annual Meeting, California Physical Therapy Association, San Diego, California, Sept. 16, 2017.
  17. Sum JC, Reeves L. Pain Rehabilitation: Physical & Occupational Therapies. Session presentation, Keck Medicine of USC 8th Annual Pain Management Symposium, Universal City, California, Aug. 11, 2017.
  18. Badash BA, Wu B, Berger M, Lorenzana D, Lane C, Sum JC, Hatch GF, Schroeder ET. Testosterone supplementation increases lean mass in men undergoing anterior cruciate ligament reconstruction: a randomized controlled trial. Abstract/Presentation. Annual Meeting. American Orthopedic Society for Sports Medicine, Toronto, Canada, July 21, 2017.
  19. Hankard J, Sum JC, Tate AR, Blubello A, Blum B, Bryant M, Chang J, Curran J, Peterson A, Weedman C, Yim C, Zeiger B. Prevalence of shoulder pain in United States youth competitive swimmers. Poster Presentation, Combined Sections Meeting, American Physical Therapy Association, San Antonio, Texas, Feb. 17, 2017.
  20. Sum JC.  Latarjet vs. Bankart: Outcomes and Rehab. Session presentation, USC Shoulder Update 2016, USC Division of Biokinesiology and Physical Therapy, Los Angeles, California, Sept.10, 2016.
  21. Sum JC, Uyeshiro A. Pain Rehabilitation: Physical & Occupational Therapies. Session presentation, Keck Medicine of USC 7th Annual Pain Management Symposium, Universal City, California, Aug. 19, 2016.
  22. Hankard J, Bryant M, Zeiger B, Yim C, Weedman C, Curran J, Tate AR, Sum JC. Prevalence of shoulder pain and disability in youth competitive swimmers.  Poster presentation, USC Division of Biokinesiology and Physical Therapy Jacqueline Perry Research Day, Los Angeles, California, April 14, 2016.
  23. Hankard J, Bryant M, Zeiger B, Yim C, Weedman C, Curran J, Tate AR, Sum JC. Prevalence of shoulder pain and disability in youth competitive swimmers.  Poster presentation, USC Ostrow School of Dentistry Research Day, Los Angeles, California, March 9, 2016.
  24. Selby-Silverstein L, Bose S, Moore MG, Sum JC, Tilson JK. Electronic Health Records and EBP: Maximizing Knowledge Translation. Session Presentation, Evidence-Based Practice Special Interest Group, Research Section, Combined Sections Meeting, American Physical Therapy Association, Anaheim, California, Feb. 20, 2016.
  25. Hawkins AP, Sum JC, Kirages D, Sigman E, Sahai-Srivastava S. Pelvic osteomyelitis presenting as groin and medial thigh pain: a resident’s case problem. Poster presentation, Combined Sections Meeting, American Physical Therapy Association, Anaheim, California, Feb. 18, 2016.
  26. Sum JC, Tate AR, Chang J, Wyberg G. Prevalence of shoulder pain and disability in youth male and female swimmers: a multicenter survey. Platform presentation, Annual Meeting, American Society of Shoulder and Elbow Therapists, Asheville, North Carolina, Oct. 9, 2015.
  27. Chang J, Skinner CB, Sum JC, Nash JK, Koshkaryan G, Hatch GF, Ji L, Groshen SL. Pre-participation fitness characteristics of participants joining Crossfit. Poster presentation, Annual Meeting, California Physical Therapy Association, Pasadena, California, Sept. 27, 2015.
  28. Merriam P, Sniderman M, Sum JC, Uyeshiro A, Weinstein FF. Case study discussion/Panel of interdisciplinary pain experts. Panel presentation, Keck Medicine of USC 6th Annual Pain Management Symposium, Pasadena, California, Aug. 20, 2015.
  29. Axtell S, Sum JC, Uyeshiro A. Pain rehabilitation: psychology, physical therapy, and occupational therapy. Panel presentation, Keck Medicine of USC 6th Annual Pain Management Symposium, Pasadena, California, Aug. 21, 2015.
  30. Dexheimer JD, Orozco SP, Wu B, Sum JC, Gilbert PK, Vallejo AF, Schroeder ET. Anti-Gravity Treadmill Walking in Acute Rehabilitation of Total and Partial Knee Replacement Patients: 1365 Board# 158 May 28, 9: 00 AM-10: 30 AM. Medicine & Science in Sports & Exercise. 2015 May 1;47(5S):363-4.
  31. Sum JC, Skinner CB, Nash JK, Koshkaryan G, Hatch GF, Ji L, Groshen SL.  Risk factors associated with shoulder injury in high-intensity exercise. Poster presentation, USC Division of Biokinesiology and Physical Therapy Jacqueline Perry Research Day, Los Angeles, California, April 16, 2015.
  32. Sum JC, Tate AR, Chang J, Wyberg G, Zeiger B. Prevalence of shoulder pain and disability in youth male and female competitive swimmers: a multicenter survey. Poster presentation, USC Division of Biokinesiology and Physical Therapy Jacqueline Perry Research Day, Los Angeles, California, April 16, 2015.
  33. Sum JC, Skinner CB, Nash JK, Koshkaryan G, Hatch GF, Ji L, Groshen SL.  Risk factors associated with shoulder injury in high-intensity exercise. Poster presentation, USC Ostrow School of Dentistry Research Day, Los Angeles, California, March 25, 2015.
  34. Sum JC, Tate AR, Chang J, Wyberg G, Zeiger B. Prevalence of shoulder pain and disability in youth male and female competitive swimmers: a multicenter survey. Poster presentation, USC Ostrow School of Dentistry Research Day, Los Angeles, California, March 25, 2015.
  35. Dayal R, Merriam P, Sniderman M, Sum JC, Uyeshiro A, Weinstein FF.  Pain management case studies: Panel discussion. Panel presentation, Keck Medicine of USC 5th Annual Pain Management Symposium, Los Angeles, California, Aug. 21, 2014.
  36. Wu B, Berger M, Sum JC, Hatch GF, Schroeder ET. Acute vs. chronic knee injury – Basketball. Platform presentation, 61st Annual Meeting, American College of Sports Medicine, Orlando, Florida, May 28, 2014.
  37. Sum JC, Skinner CB, Kim SC, Kelso AS, Hatch GF, Groshen SL. Pilot study to investigate risk factors associated with shoulder injury in athletes involved with CrossFit.  Poster presentation, USC Division of Biokinesiology and Physical Therapy Jacqueline Perry Research Day, Los Angeles, California, April 17, 2014.
  38. Sum JC, McGuiness A, Hatch GF. Range of motion and self-reported outcome measures following latissimus dorsi tendon transfer for irreparable rotator cuff tear using a post-operative physical therapy protocol: A case series. Platform presentation, Annual Meeting, American Society of Shoulder and Elbow Therapists, Las Vegas, Nevada, Oct. 13, 2013.
  39. Sum JC, Fitzgerald K, Haile J, McNeill B, Michener LA. Relevance of scapular dyskinesis in patients with shoulder pain. Poster presentation, USC Division of Biokinesiology and Physical Therapy Jacqueline Perry Research Day, Los Angeles, California, April 11, 2013.
  40. Sum JC, Fitzgerald K, Haile J, McNeill B, Michener LA. Relevance of scapular dyskinesis in patients with shoulder pain. Poster presentation, USC Ostrow School of Dentistry Research Day, Los Angeles, California, Feb. 20, 2013.
  41. Tilson JK, Mickan S, Sum JC, Zibell M, Howard R, Dylla J. Impact and implications of a multi-faceted, participant driven, EBP educational intervention. Evidence 2011, London, England, October 2011.
  42. Woodward SC, Hayden EM, Sum JC, Fresen JL, Dylla JM, Ying JC. Physiologic characteristics of jazz guitarists. Platform presentation, Medical Problems of Performing Artists Annual Symposium, Performing Arts Medicine Association, Snowmass, Colorado, July 2010.
  43. Sum JC. Latissimus dorsi tendon transfer for massive irreparable rotator cuff tears: indications and post-operative rehabilitation considerations. Poster presentation, Combined Sections Meeting, American Physical Therapy Association, Las Vegas, Nevada, February 2009.
  44. Sum JC, Ellenbecker TS, Bailie DS. Range of motion, rotator cuff muscular strength, and functional self-report following Promos shoulder arthroplasty vs. Copeland shoulder arthroplasty. Platform presentation, Combined Sections Meeting, American Physical Therapy Association, San Diego, California, February 2006.
  45. Sum JC, Popovich JM, Kulig K, Colletti P. The role of axial loading in early diagnosis of lumbar disc injury: a biomechanical interpretation using magnetic resonance imaging. Poster presentation, Combined Sections Meeting, American Physical Therapy Association, New Orleans, Louisiana, February 2005.

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