Sports Medicine Research: In the Lab & In the Field: Additional Perturbation Not Necessary (Sports Med Res)


Wednesday, March 22, 2017

Additional Perturbation Not Necessary

Report of the Primary Outcomes for Gait Mechanics in Men of the ACL-SPORTS Trial: Secondary Prevention With and Without Perturbation Training Does Not Restore Gait Symmetry in Men 1 or 2 Years After ACL Reconstruction.

Capin JJ, Zarzycki R, Arundale A, Cummer K, and Snyder-Mackler L. Clin Orthop Relat Res.  2017. [Epub Ahead of Print].

Report of the Clinical and Functional Primary Outcomes in Men of the ACL-SPORTS Trial: Similar Outcomes in Men Receiving Secondary Prevention With and Without Perturbation Training 1 and 2 Years After ACL Reconstruction.

Arundale A, Cummer K, Capin JJ, Zarzycki R, and Snyder-Mackler L. Clin Orthop Relat Res.  2017. [Epub Ahead of Print].

Take Home Message: There is no benefit of adding perturbation training to the ACL-SPORTS training program between 3 to 9 months following an ACL reconstruction.

Knee function often improves over 2 years after an anterior cruciate ligament (ACL) injury; however, athletes are usually discharged from rehabilitation and returned to play before then. Clinicians need rehabilitation protocols that help athletes improve after completing a traditional rehabilitation protocol, when they return to play. Therefore, Capin and Arundale present 2 articles describing a randomized trial intended to identify the effectiveness of adding perturbation training to the Anterior Cruciate Ligament Post-Operative Return-to-Sport (ACL-SPORTS) training program. The authors conducted a single-blind randomized clinical trial that included 40 male athletes with isolated, unilateral ACL tears (15-54 years old, 27 autographs, 13 allografts). All participants completed a post-operative ACL rehabilitation protocol and were 3 to 9 months post-ACL reconstruction. During the study, participants attended treatment sessions 2 times per week for a total of 10 sessions. Following treatment, Arundale and colleagues assessed lower limb symmetry during several hop tests and quadriceps strength testing at 1- and 2-years post-surgery. A total of 36 participants (19 with perturbation, 17 non-perturbation) completed the 1- and 2-year follow up visits. Overall, participants who completed the perturbation training failed to experience better self-reported or functional outcomes than those who only completed the ACL-SPORTS protocol. Capin and colleagues assessed gait mechanics and found gait asymmetries (involved vs. uninvolved limb) in both treatment groups. They found no differences between treatment groups. Overall, both studies indicate that adding perturbation training to the ACL-SPORTS program fails to improve either clinical outcomes or gait patterns compared to ACL-SPORTS training alone. 

Overall, both studies suggest clinicians do not need to add perturbation training to the ACL-SPORTS protocol 3 to 9 months following an ACL reconstruction. However, some caution should be taken when interpreting these results. Most significant is the lack of demographic information given regarding participants of the study, especially regarding previous activity level. Furthermore, these studies only included males even though the study is also recruiting women. Adding these extra details and reporting on the women and men would allow clinicians to generalize these results to a broader patient population. Also of interest is the lack of any baseline data. While not feasible in the current study, baseline data is something that future research should strive for as it would help clinicians understand the impact of the gait analysis data much better. Ideally, this baseline data would be collected pre-injury so the results can be compared to the participant’s natural gait. This does, however bring with it methodological restrictions. Still it would be informative to at least know more about the gait and limb symmetry before the start of the intervention.  Until more research can be completed to address these limitations, clinicians should continue the use of ACL-SPORTS training program without perturbation training.

Questions for Discussion: Do you agree with the overall finding that perturbation training does not significantly improve outcomes? If not, what tell us what clinical experience you have with perturbation training.

Written by: Kyle Harris
Reviewed by:  Jeffrey Driban

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Alexandra DeJong said...

This article was successful in exploring an additional tool to use in ACLR subjects, and raised good clinical questions in how we should intervene to improve outcomes. The limitations mentioned in this summary are very important to consider, but it is also important to consider how perturbation training may affect mechanics in other tasks, such as jump landing as this is the position in which many non-contact ACL ruptures occur. Although the perturbation training did not directly translate to improved symmetry in gait, that does not mean there would not be improvements in other areas that may be clinically meaningful for ACLR patients. Additionally, it would be important to see how patient's subjective scores may have changed in terms of kinesiophobia or perceived improvements following perturbation training.

Kyle Harris said...


Excellent point! I would keep an eye out for more publications from this group who are using the same participants and standardization with different variables. I also agree with your point that 1 method of training should never been stopped or avoided because it does not help fix 1 problem. The body of literature may suggest another very beneficial improvement that perturbation training elicits and as clinicians we should do our best to identify the need and employ the best possible treatments. What variables have you found perturbation training to be especially helpful with treating? Thanks for the comment!


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