One of the most devastating injuries for the active sporting population is an anterior cruciate ligament (ACL) rupture. This is a complete tear of one of the important ligaments that maintains knee joint stability. A rupture of the ACL can cause significant initial pain and requires a lengthy rehabilitation process. The majority of people require surgery for a full recovery. This blog outlines the risk factors for an ACL injury and how we can work with you to reduce your risk.
Firstly, it’s important to appreciate the huge potential for preventative measures to protect the ACL from injury. It has been found that 60-80% of ACL ruptures occur in non-contact situations. This means that the injury is a result of poor muscular control and biomechanics rather than the influence of an unexpected external force (such as a tackle from an opposing player, which would be considered a contact injury). This means we have control over the main factors leading to ACL injury. Through specific exercises we can influence muscular control and biomechanics for the better.
Assessing your risk
ACL injuries are common in field and court sports, and other sports that require running with fast changes of direction, combined with jumping and landing.
The typical mechanism of a non-contact ACL rupture is a forceful movement of the leg rotating inwards and the foot collapsing, causing the knee to twist forcefully inwards.
A simple test to assess your risk of getting into the position is the lateral step-down test. Start from an elevated height such as a step and step down with one foot. As you descend you may notice that your knee rotates in. This may become more apparent in a more dynamic movement, just as in sport, such as hopping down from the step and assessing whether your knee rotates inwards as you land. This is easiest to assess if you get someone else to video you, so you can watch from the front. If you complete these tests and the knees move into this risky position, there are a few factors to address. If your positioning is good with the knee staying in line with the hips and foot, this indicates you have a decreased risk (but definitely not no risk) of ACL injury.
Causes of poor knee control
There are two common mobility issues that cause the knee to move into this position. Inadequate hip and ankle mobility are commonly compensated for by rotation of the leg.
From a strength perspective it is weakness in the glutes and hamstring muscles that increases your risk of ACL injury. The glutes control rotation movements of the leg and stabilise when standing on one leg. They therefore have a big influence as to whether your knee has a tendency to rotate inwards into the dangerous position for ACL injury. The hamstrings have the ability to reduce the forward movement of the lower leg on the upper leg, which is the other common factor in ACL injuries.
Reducing your risk - what can BeachLife Physio do?
Mobility and strength tests performed by your physiotherapist can differentiate which of the above is the cause of your poor knee positioning and control. We then provide the appropriate strength and mobility exercises to decrease your risk of injury. This is best completed early in the off season of your sport, to ensure you are prepared for your sport once the season starts!
If you have poor knee control, want to reduce your risk of injury, or need advice on any of the above please do not hesitate to call us to book an appointment on 9970 7982, or alternatively book online.
Norcross, M. F., Halverson, S. D., Hawkey, T. J., Blackburn, J. T., Padua, D. A. (2009) Evaluation of the Lateral Step-Down Test as a Clinical Assessment of Hip Musculature Strength. Athletic Training & Sports Health Care, vol. 1, iss. 6.
Yonz, M. C. Robertson, K. E., McKinley, R. et al. (2016) Relationship of Hip and Trunk Muscle Function with Single Leg Step-Down Performance: Implications for Return to Play Screening and Rehabilitation. Physical Therapy in Sport, vol 22, pp. 66-73.