Hop – hop – hop!! Easter is almost here and with it comes the hip-hopping Easter Bunny to deliver all that delicious chocolate! From a physio’s perspective, I’ve always wondered what the Easter Bunny does to keep his bunny-knees injury free as prolonged and repetitive jumping can be hard on the knees!
As Evel Knievel states, “Anybody can jump…The trouble begins when you try to land.” (1).
Believe it or not, Anterior Cruciate Ligament (ACL) tears of the knee more commonly occur from NON-CONTACT mechanisms than direct contact (2). ie. The injury does not involve the Easter Bunny being tackled by the Tooth Fairy or colliding with Santa’s sleigh. Non-contact mechanisms typically include “plant and twist” (such as with cutting) maneuvers or jumping – *ahem!* specifically LANDING (especially in the “knee-in and toe-out” or knee valgus position) (2).
In a sexist twist of fate, unfortunately females (after onset of puberty) are 2-10x more likely than male teammates to injure their ACL in jumping and landing sports (3). Once you’ve had an ACL injury, you’re also 15-25x more likely to either re-injure the same knee or injure your other knee during these cutting & jumping sports (3). In case you need more “not-so-fun” facts to make you want to prevent an ACL injury, once you’ve had an ACL injury, you’re also more likely to develop knee osteoarthritis sooner – within 12-20 years after the original injury (3,4).
(It’s okay if you don’t feel like hopping for joy after all this bad news.) But not to fear – the Easter Bunny Physio is here!!
After close analysis of the Easter Bunny’s Bio-hopping-mechanics, it appears that he uses 4 techniques (which luckily are adaptable to the human physique…) to minimize his risk of ACL injury. Here’s what you can do too:
Land with your knee in the same plane as your toe (think “knee in line with toes”) – ie. avoid the “knee-in and toe-out” position, thereby placing less stress on the ligament (4,5)
Land with your knees and hips more flexed (think “deeper squat” or in a sport “ready position”). This technique not only helps “soften” the landing, allowing more time to absorb the shock (6), but also this physical alignment puts the hamstrings in a better position to support the ACL, taking some load off the ligament. (4,5)
Land with weight evenly distributed between both feet (think “50-50”)(4). It’s pretty common to have a dominant leg and a resultant reliance and slight lean to one side (5).
Have good core or trunk control (eg if someone pushes you at the bottom of your “landing”, you won’t fall over) (4,5)
This is a lot to think about during a movement that only lasts approximately 1 second (with the majority of the shock absorption phase taking less than a quarter of a second) (6). Instead, I recommend focusing on landing “softly” (like a ninja!) – or using a target (such as a traffic cone) for your knee to touch at the bottom of your landing (7).
For more information about jumping, landing, and ACL injuries, and/or help making an exercise plan that is right for you, contact InReach Physio.
By: Susan “Hop-along” Herdman, Registered Physiotherapist
Book a telephysio / online physio / virtual physio / video physiotherapy appointment with a registered physiotherapist in British Columbia. InReach Online Physio services communities in northern and rural BC, such as Masset, Queen Charlotte, Fraser Lake, Fort Nelson, Fort St James, Dease Lake, Fort St John, Dawson Creek, the Gulf Islands, and more!
REFERENCES:
1) Knievel, E on Brainy Quote. (2022) Evel Knievel Quotes: Accessed Mar 18/22: https://www.brainyquote.com/quotes/evel_knievel_601462
2) Kobayashi H, Kanamura T, Koshida S, et al. Mechanisms of the anterior cruciate ligament injury in sports activities: a twenty-year clinical research of 1,700 athletes. J Sports Sci Med. 2010;9(4):669-675. Published 2010 Dec 1. Accessed Mar 18/22: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761820/
3) Hewett TE, Myer GD, Ford KR, Paterno MV, Quatman CE. Mechanisms, prediction, and prevention of ACL injuries: Cut risk with three sharpened and validated tools. J Orthop Res. 2016;34(11):1843-1855. doi:10.1002/jor.23414. Accessed Mar 18/22: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5505503/
4) Lopes, T., Simic, M., Myer, G. D., Ford, K. R., Hewett, T. E., & Pappas, E. (2018). The Effects of Injury Prevention Programs on the Biomechanics of Landing Tasks: A Systematic Review With Meta-analysis. The American journal of sports medicine, 46(6), 1492–1499. Accessed Mar 18/22: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6604048/
5) Hewett TE, Ford KR, Hoogenboom BJ, Myer GD. Understanding and preventing acl injuries: current biomechanical and epidemiologic considerations - update 2010. N Am J Sports Phys Ther. 2010;5(4):234-251. Accessed Mar 18/22: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3096145/
6) Ortega DR, Rodríguez Bíes EC, Berral de la Rosa FJ. Analysis of the vertical ground reaction forces and temporal factors in the landing phase of a countermovement jump. J Sports Sci Med. 2010;9(2):282-287. Published 2010 Jun 1. Accessed Mar 18/22: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761745/
7) Gokeler, A. (2017 Dec 29) TrustMe Ed Online Lecture: Applying Principles of Motor Learning to ACL Rehab. Accessed July 2021: https://www.trustme-ed.com/lectures/applying-principles-of-motor-learning-to-acl-rehab