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Neural contribution to ACL injury

Updated: Feb 21, 2020

“I’ve torn my knee ligament while playing pickle ball. No one touched me. All I did was simply hopping sideways to receive the ball. Why would my own movement get me injured like this? What can I do to make sure that this does not happen again?” We hear this kind of question quite often from many of our clients. We've seen a huge development in understanding biomechanical mechanisms of the non-contact injuries during the past decade. One of the most commonly known mechanisms is that the knee does not align properly when our lower body deals with the impact forces from the ground (as in landing after a jump). For this reason, fitness trainers and coaches these days provide their clients with the exercises that focus on stabilizing the knee position while bending and straightening the knees in a weight bearing position. While this is a necessary training method, we also need to help the person develop the ability to control the joint stability in an environment where the stability is challenged in a random manner. How can we achieve this?

We have stepped into an exciting era where we get to know more and more about neural contribution to the non-contact injuries. A recent study by Diekfuss et al. (2018) showed how the neural activity characteristic before the competitive season affected traumatic injuries to the athletes' anterior cruciate knee ligaments (ACL) occurred during the season. This study was conducted on 57 female high school soccer players. The investigators used functional magnetic resonance imaging (fMRI) of the brain. They found that lower functional connection between the sensory-motor region and a cerebellar region was associated with higher incidence rate. It was indicated by the decreased synchrony between black and red line in the graph shown below. The connection between these brain regions is critical for balance and coordination. It is also known that tasks which require the brain to continuously make decisions regarding both timing and amplitude of movement promote the connectivity within sensory and cerebellar regions (e.g., a soccer player predicting when and where to jump to intercept a moving soccer ball). This means that gym exercises to strengthen and solidify proper joint alignment should be combined with tasks that require the person to continuously change the timing and magnitude of movement in order to maximize the chance of preventing non-contact injuries.

This fMRI was conducted during the resting state. It would be interesting to see a follow up study that includes performance measure on balance and coordination.

Please click the reference below to access the full text article.


  1. Diekfuss, J. A., Grooms, D. R., Yuan, W., Dudley, J., Foss, K. D. B., Thomas, S., ... & Myer, G. D. (2018). Does brain functional connectivity contribute to musculoskeletal injury? A preliminary prospective analysis of a neural biomarker of ACL injury risk. Journal of science and medicine in sport.

  2. O’Reilly JX, Mesulam MM, Nobre AC. The cerebellum predicts the timing of

perceptual events. J Neurosci 2008; 28(9):2252–2260.

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