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Anterior cruciate ligament (ACL) reconstruction and running

Torn ACLs are the most common and serious ligament injury to the knee and patients who suffer from this often need surgery for reconstruction. Whether or not they are runners, all of our patients are prescribed “running” at some point of their rehabilitation. This step is especially important for patients as it is the first weight bearing sport activity they will take up, which means that it deserves special attention from clinical practitioners. When can patients resume physical activity and what are the challenges that can be anticipated? First, let’s review current scientific evidence and determine which improvements can be made to enhance patient care.




When to resume physical activity?


The initial goal is to determine, at best, the ideal time for getting back at it. If it is too soon, the clinician may endanger the health of his/her patient; and if it is too late, the clinician may lose the trust of his/her patient. Is there a set postoperative period of time after which one can safely resume physical activity? No. All studies indicate that the recovery algorithm for resuming running should be excluded. Indeed, a review of the literature has allowed us to conclude that running is not an ACL-prone activity. A systematic review conducted by Lopes et al. (2012), which includes data from 3,500 runners, has reported no torn ACL. Additionally, resuming running does not bring about secondary laxity after ACL reconstruction.1 Therefore, it is recommended to focus on criteria for progression toward recovery.2,3 These criteria include the ability of patients to tolerate impact upon contact with the ground, the quadriceps’ capacity to regain their muscle strength and knee mobility. Moreover, functional criteria such as the quality of the biomechanics when walking must also be taken into account. The literature reports that walking can be affected up to 5 years following surgery4 and that there is a strong correlation between problems experienced when walking and running.5 Reducing asymmetries when walking, before resuming running, is thus essential. By letting go of a prescribed time period and following the criteria for progression, some patients will be in a position to resume running, safely, at a very early stage of rehabilitation!


Deficiencies observed during running


Running-specific analyses have shown deficiencies following ACL reconstruction. Limited knee flexibility in the support phase has been reported.6 This limitation can be explained by less strength deployed by the quadriceps during loading of the knee and by increased activation of the hamstrings.7 Muscle activation deficiencies during high-intensity running were also observed.8 Finally, it is worth noting that patients generally experience difficulties changing their running biomechanics; consequently, adapting to a new surface (more or less hard) is relatively limited.9 As your patients have not run for a long time, rehabilitation must be progressive. Quantifying mechanical stress adequately is therefore essential. Make sure to plan for frequent trainings (4-5 per week is ideal) and alternate between running and walking (1 to 4 minutes running and 2 minutes walking at the beginning).




Take this opportunity to instill new techniques in your patients that will be beneficial down the line. Given that most patients treated with reconstruction of the ACL are likely to develop early arthritis in the knee,10 you can give them advice that will help them improve performance and, especially, reduce the pressure exerted on the knee. Increasing cadence, developing a light stride and wearing minimalist shoes (minimal index >70%) is sound advice that you can give your patients.11,12 Some will even benefit from practicing a forefoot strike.

When your patients become comfortable running and there are no apparent visual asymmetries, be mindful of quick conclusions as to their running technique. It is important to continue with more specific aspects of rehabilitation. Make sure to vary training intensity and include high-intensity training sessions. It is also recommended to run on various surfaces; e.g., trail running.



In conclusion, studies specific to runners treated with ACL reconstruction are relatively limited. However, these early results still provide us with insights on how to improve our practice and optimize patient recovery. To be continued!



  1. Dauty, M., Menu, P. & Dubois, C. Effects of running retraining after knee anterior cruciate ligament reconstruction. Ann Phys Rehabil Med 53, 150–61 (2010).
  2. Herrington, L., Myer, G. & Horsley, I. Task based rehabilitation protocol for elite athletes following Anterior Cruciate ligament reconstruction: a clinical commentary. Phys Ther Sport 14, 188–198 (2013).
  3. van Grinsven, S., van Cingel, R. E., Holla, C. J. & van Loon, C. J. Evidence-based rehabilitation following anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 18, 1128–44 (2010).
  4. Gokeler, A. et al. Return of normal gait as an outcome measurement in acl reconstructed patients. A systematic review. Int J Sports Phys Ther 8, 441–51 (2013).
  5. Sigward, S. M., Lin, P. & Pratt, K. Knee loading asymmetries during gait and running in early rehabilitation following anterior cruciate ligament reconstruction: A longitudinal study. Clin. Biomech. Bristol Avon 32, 249–254 (2016).
  6. Saxby, D. J. et al. Tibiofemoral Contact Forces in the Anterior Cruciate Ligament-Reconstructed Knee. Med. Sci. Sports Exerc. (2016). doi:10.1249/MSS.0000000000001021
  7. Hart, J. M., Pietrosimone, B., Hertel, J. & Ingersoll, C. D. Quadriceps activation following knee injuries: a systematic review. J Athl Train 45, 87–97 (2010).
  8. Patras, K. et al. High intensity running results in an impaired neuromuscular response in ACL reconstructed individuals. Knee Surg. Sports Traumatol. Arthrosc. Off. J. ESSKA 17, 977–984 (2009).
  9. Hackney, J. M., Wade, M. G., Larson, C., Smith, J. P. & Rakow, J. Impairment in people with anterior cruciate ligament reconstruction in adjusting ground reaction force in running. Physiother. Theory Pract. 26, 289–296 (2010).
  10. Simon, D. et al. The Relationship between Anterior Cruciate Ligament Injury and Osteoarthritis of the Knee. Adv. Orthop. 2015, 928301 (2015).
  11. Heiderscheit, B. C., Chumanov, E. S., Michalski, M. P., Wille, C. M. & Ryan, M. B. Effects of step rate manipulation on joint mechanics during running. Med. Sci. Sports Exerc. 43, 296–302 (2011).
  12. Rice, H. M., Jamison, S. T. & Davis, I. S. Footwear Matters: Influence of Footwear and Foot Strike on Loadrates During Running. Med. Sci. Sports Exerc. (2016). doi:10.1249/MSS.0000000000001030



Benoit Pairot de Fontenay