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A Preliminary Study of Subsymptom Threshold Exercise Training for Refractory Post-Concussion Syndrome

Leddy, John J MD*†; Kozlowski, Karl PhD; Donnelly, James P PhD§; Pendergast, David R EdD; Epstein, Leonard H PhD; Willer, Barry PhD**

Clinical Journal of Sport Medicine: January 2010 - Volume 20 - Issue 1 - p 21-27
doi: 10.1097/JSM.0b013e3181c6c22c
Original Research

Objective: To evaluate the safety and effectiveness of subsymptom threshold exercise training for the treatment of post-concussion syndrome (PCS).

Design: Prospective case series.

Setting: University Sports Medicine Concussion Clinic.

Participants: Twelve refractory patients with PCS (6 athletes and 6 nonathletes).

Intervention: Treadmill test to symptom exacerbation threshold (ST) before and after 2 to 3 weeks of baseline. Subjects then exercised 5 to 6 days per week at 80% ST heart rate (HR) until voluntary peak exertion without symptom exacerbation. Treadmill testing was repeated every 3 weeks.

Main Outcome Measures: Adverse reactions to exercise, PCS symptoms, HR, systolic blood pressure (SBP), achievement of maximal exertion, and return to work/sport.

Results: Pretreatment, ST occurred at low exercise HR (147 ± 27 bpm) and SBP (142 ± 6 mm Hg). After treatment, subjects exercised longer (9.75 ± 6.38 minutes to 18.67 ± 2.53 minutes, P = .001) and achieved peak HR (179 ± 17 bpm) and SBP (156 ± 13 mm Hg), both P < .001 versus pretreatment, without symptom exacerbation. Time series analysis showed significant change in rate of symptom reduction for all subjects and reduced mean symptom number in 8/11. Rate of PCS symptom improvement was related to peak exercise HR (r = −0.55, P = .04). Athletes recovered faster than nonathletes (25 ± 8.7 vs 74.8 ± 27.2 days, P = .01). No adverse events were reported. Athletes returned to sport and nonathletes to work.

Conclusions: Treatment with controlled exercise is a safe program that appears to improve PCS symptoms when compared with a no-treatment baseline. A randomized controlled study is warranted.

From the *Department of Orthopaedics; †the Sports Medicine Institute; Departments of ‡Exercise and Nutrition Sciences; §Counseling, School and Educational Psychology; ¶Physiology and Biophysics; ∥Pediatrics; and **Psychiatry, University at Buffalo, The State University of New York, Buffalo, New York.

Submitted for publication March 10, 2009; accepted October 19, 2009.

Funding for this research was provided in part by a grant from the New York State Athletic Trainers' Association.

The authors report no professional relationships with companies or manufacturers who will benefit from the results of the present study.

Reprints: John J. Leddy, MD, FACSM, FACP, University Sports Medicine, 160 Farber Hall, 3435 Main St, Buffalo, NY 14214 (e-mail:

© 2010 Lippincott Williams & Wilkins, Inc.