Preventing non-contact ACL Ruptures in Field and Court Athletes

 In Lower Limb


The Anterior Cruciate Ligament (ACL) is a ligament in the knee which stops the shin sliding forward relative to the thigh bone. When ruptured it will most often require surgery to repair (if you want to be able to return to sport). ACL reconstructive surgery is an expensive exercise costing on average $11 157 (Gianotti et al., 2009) for surgery alone, not including the process from initial through to end stage rehab or missed work. It is also painstakingly slow to recover from and the source of much frustration in elite and amateur athletes. Gobbi and Francisco (2006) found that only 65% of athletes who suffer an ACL rupture are able to return to sport at the same level they were competing at pre-injury. General post operative care requires at least one week on crutches followed by a gradual return to daily activities. Return to sport is usually more than 12 months with running commencing in between 6 and 9 months. ACL reconstruction is also linked to early onset of knee Osteoarthritis which adds to the devastating short term effects.

The injury is severe however it is also becoming more common. Female athletes are thought to be 2-5 times more times likely to rupture an ACL than males (Arendt, Agel and Dick, 1999). The rise in popularity in female field sports such as AFL and Rugby 7’s has also coincided with an increased incidence of female ACL ruptures. The most common sports for ACL ruptures across both genders in Australia include Netball, Skiing, Australian Rules Football, Rugby Union, Rugby League, Rugby 7’s, Hockey, Basketball and Soccer.

Knowing the severity, cost and incidence of ACL injuries it makes sense that we attempt to curb the incidence of these injuries, after all, “Prevention is Better than the Cure”.

Prevention is Better than the Cure @pogophysio #performbetter Click To Tweet

So what CAN we do to help our bodies be better prepared?

First we must understand the bio-mechanics of an ACL injury. There are 3 main ways that an ACL can be stressed (not including outside contact because that is hard to control!)

  1. Excess Valgus of the Knee ie knees pointing inward
  2. Excess External femoral rotation ie thigh twisting outwards and lower leg twisting inward ( to demonstrate stand feet shoulder width apart and twist your trunk to look over one shoulder, you will feel the twisting force on the foot your twisting away from)
  3. Poor muscular strength/control in the coronal plane (think straight line running)

(Koga et al., 2016)

So what can we do to minimise the ACL stressing factors above:

Neuromuscular training has been shown to be highly effective in reducing ACL rupture incidence (Silvers and Mandelbaum, 2007). Luckily for us, preventing the knee from collapsing inward (point 1) and preventing the lower leg from twisting inwards (point 2) have similar methods. We must make sure you have strong external rotators and abductors of the hip, most notably the gluteal muscles (Khayambashi et al., 2015), have adequate strength from the calf complex and stability from the foot and be able to recruit the strength you possess to adapt safe techniques when landing and changing directions. We also must (point 3) make sure you have adequate hamstring plus hip extension (gluteus maximus) strength and have equal opposing strength coming from your quads.

Landing and changing direction is a skill that needs to be trained. Once you have the strength to control your knees, you also need to learn how to land and change directions so that you avoid excess strain on the knee.

This includes:

  1. Keeping knees from collapsing inward
  2. Softening the hips
  3. Keeping some bend in the knees
  4. Keeping thigh’s rotated outward

How do I address all of the above?

Firstly, any attention devoted toward minimising your risk of injury is better than none! If you would like a great free resource for coaches and athletes of any level, the Australian Netball Association released an excellent knee injury prevention program aptly named ‘KNEE’ and it is a great place to start.

If you would like to be more specific with tailoring a program for YOU, then physio is a great place to start, we can assess your individual needs and help set you up with a gym and home program to help minimise your injury risk, and as a handy bonus, increase your performance!

More information to come on specific predictors and exercises to focus on!

Michael Harders
Master Physiotherapist

Michael Harders

Featured in the Top 50 Physical Therapy Blog


Arendt, E., Agel, J. and Dick, R. (1999). Anetrior Cruciate Ligament Injury Patterns Among Collegiate Men and Women. Journal of Athletic Training, [online] 34(2), pp.86-92. Available at: [Accessed 19 Oct. 2017].

Gianotti, S., Marshall, S., Hume, P. and Bunt, L. (2009). Incidence of anterior cruciate ligament injury and other knee ligament injuries: A national population-based study. Journal of Science and Medicine in Sport, 12(6), pp.622-627.

Gobbi, A. and Francisco, R. (2006). Factors affecting return to sports after anterior cruciate ligament reconstruction with patellar tendon and hamstring graft: a prospective clinical investigation. Knee Surgery, Sports Traumatology, Arthroscopy, 14(10), pp.1021-1028.

Khayambashi, K., Ghoddosi, N., Straub, R. and Powers, C. (2015). Hip Muscle Strength Predicts Noncontact Anterior Cruciate Ligament Injury in Male and Female Athletes. The American Journal of Sports Medicine, 44(2), pp.355-361.

Koga, H., Muneta, T., Bahr, R., Engebretsen, L. and Krosshaug, T. (2016). ACL Injury Mechanisms: Lessons Learned from Video Analysis. Rotatory Knee Instability, pp.27-36.

Silvers, H. and Mandelbaum, B. (2007). Prevention of anterior cruciate ligament injury in the female athlete. British Journal of Sports Medicine, 41(Supplement 1), pp.i52-i59.

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