Later that same year, Gilbert et al Sport Health 2016 published a paper that looked at the correlation of concussion to all lower kinetic chain musculoskeletal injuries and length of time since the concussion. What the authors found here was that Division I athletes who suffered a concussion were at 1.6 to 2.9 times greater risk for a non-contact ankle and/or knee injury up to 2 years post concussion. This is telling as we are not only seeing the impact on all lower kinetic chain injuries but also how long this impacts the athlete. Further, McPherson et al Am J Sport Med 2018 performed a systematic review and meta-analysis looking at research from 2000 - 2017. Based on the meta-analysis, the authors concluded that athletes with a concussion are at 2xs greater risk of lower kinetic chain musculoskeletal injury than non-concussed athletes.
If you are like me, you may be asking yourself, why is this the case. We know that there are some vestibular and balance issues that can persist after a concussion, but how does that impact lower kinetic chain injuries? Since 2016, we have been tracking concussion history and movement data with an inertial measurement unit (IMU via DorsaVi ViPerform AMI). Since this time, we have collected movement data on over 11,200 athletes. That means we have movement data on >930,000 reps, >33,000 minutes of core testing and over 11,200,000 variables. With this level of data, it is allowing us to see movement trends prior to being published in the research. Some current trends we have identified are:
- Those with a history of concussion have a larger magnitude of frontal plane motion than non-concussed athletes. This is measured in single limb activities, specifically a single leg squat, single leg hop and single leg hop plant. During these activities, the magnitude of varus to valgus motion at landing is much greater in those with a history of concussion.
- Those with a history of concussion have higher speeds of valgus than non-concussed athletes. This is also measured in single limb activities, specifically a single leg squat, single leg hop and single leg hop plant. During these activities, the speed at which the knee falls into valgus is much greater or faster in those with a history of concussion. This is a huge risk factor for knee and ACL injury.
- Those with a history of concussion have a greater time to stability than non-concussed athletes. Time to stability is the amount of time that it takes for the athlete to be stable once they land. Some athletes, once they land, they will have multiple hops before they become stable. The longer they hop, the greater their time to stability. What we do is time stamp the time they first land to the time it takes them to become stable. This is measured in single limb hopping activities, specifically the single leg hop and single leg hop plant. During these activities, the time that it takes for an athlete to become stable is much greater in those with a history of concussion.
In addition to the above, something else that we see is an increase in center of mass (COM) displacement, especially in single limb activity. We will look at this in more detail next week. If you enjoy this blog, please share with your colleagues and follow us on instagram @ bjjpt_acl_guy and twitter at @acl_prevention. #ViPerformAMI #ACLPlayItSafe