04 Sep ACL Injuries and Landing Strategies
Marc F. Norcross, PhD, ATC
School of Biological & Population Health Sciences, Exercise & Sport Science Program
College of Public Health and Human Sciences
Oregon State University
Corvallis, OR 97331
MedicalResearch.com: What are the main findings of the study?
Dr. Norcross: In the scientific community, there remains considerable disagreement over which direction of knee loading is most responsible for causing an anterior cruciate ligament (ACL) injury event. Many researchers tend to fall into one of three “camps” in which they believe quadriceps loading (sagittal plane), “knock-kneed” landing (frontal plane), or twisting (transverse plane) is the essential factor in the injury mechanism. However, we know from cadaver studies that combined loading from all of these different planes puts the most strain on the ACL. We found that men and women are equally likely to use a sagittal plane landing strategy that we believe increases the risk for ACL injury. However, females were about 3.6 times more likely than males to use a higher risk frontal plane landing strategy. This suggests that the increased likelihood of greater frontal plane loading in women coupled with the equal likelihood of using a high-risk sagittal plane strategy is likely at least partly responsible for women’s 2-6 times greater risk for ACL injury.
MedicalResearch.com: Were any of the findings unexpected?
Dr. Norcross: We expected that the same individuals who use a high-risk sagittal plane landing strategy would also be the ones to use a high-risk frontal plane landing strategy. However, we did not find any relationship between the sagittal and frontal plane landing strategies of individuals in this study. Given our findings, we proposed that individuals at the greatest risk for ACL injury are likely to be the ones who land using a high-risk sagittal plane and a high-risk frontal plane landing strategy. This is because the way in which these individuals move is likely consistently placing greater combined loading on the ACL. So, when they perform a difficult or very explosive task, it could result in an excessively high load that may cause the ligament to fail.
MedicalResearch.com: What should clinicians and patients take away from your report?
Dr. Norcross: It is important to think about the total package related to landing technique and not just one aspect like being “knock-kneed” or stiff.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Dr. Norcross: The use of currently available ACL injury intervention programs are a great way to teach safer landing strategies and have been shown in controlled studies to reduce the risk for ACL injury. However, in my opinion, we must improve the way in which these programs are packaged so that there is widespread implementation by coaches and health care professionals. Until we do so, I believe that we are going to continue to face an uphill battle in reducing the ACL injury rate at the population level.
Ankle-Dorsiflexion Range of Motion and Landing Biomechanics
Chun-Man Fong, LAT, ATC; J. Troy Blackburn, PhD, ATC; Marc F. Norcross, MA, ATC; Melanie McGrath, PhD, ATC; Darin A. Padua, PhD, ATC