ACL Injuries in Sport
The prevalence of anterior cruciate ligament (ACL) injuries in sport has not changed significantly over time, with the International Olympic Committee reporting 34-80 non-contact ACL injuries per 100,000 athletes (Renstrom, et al, 2008).
There have been numerous studies conducted about the mechanisms and risk factors for all ACL injuries in sport. Risk factors include: knee joint laxity, knee joint anatomy, greater body mass, increased height, increased BMI (Serpell, Scarvell., et al, 2012), strength levels, fatigue levels, and neuromuscular control ( Herman, Onate et al, 2009). It is quite evident that an overall strength & conditioning program including strength exercises and conditioning protocols that also achieve body fat levels within recommended guidelines will reduce some of the identified risks.
A more comprehensive approach is to ensure that your strength & conditioning program is designed to be more sport specific, to address more of the identified risk factors and reduce the potential issues that occur in game day or training scenarios. Herman et al (2009) reported that strength alone did not alter knee joint kinematics for landing tasks, but strength work combined with skills to land correctly did have benefits. Neuromuscular control which includes muscle strength, power and activation patterns (Myer, Ford., et al, 2012), needs to be a part of sport specific programming. Quadriceps and hamstring strength are areas to focus on to reduce the opportunity for ACL injury, as hamstring activation at the correct time of knee flexion can decrease ACL loading. Quadriceps strength activation at the correct time, by way of recruitment in sport type movements, provides an agonistic role and assists in ACL protection (Myer, Ford., et al, 2012).
If you are currently training and playing sport, your program should be addressing the basic requirements of your sport, such as strength, conditioning and flexibility. Drills that demand neuromuscular control should be incorporated into this training cycle to assist with the high demands of sport, whether social or competitive. Neuromuscular training has been researched quite extensively and in summary, proprioceptive acuity is important in “switching on” relevant muscles, such as hamstring activation prior to foot strike. In relation to the ACL, the inclusion of dynamic knee joint stability exercises tends to support reductions in incidences of ACL injury.
Change of direction (COD) drills, sidestep drills, and agility training assist in developing knee strength and this type of training would ensure appropriate recruitment patterns are being trained (Serpell, Scarvell., et al, 2012). The progression from training controlled scenarios; jump & stick, bounds, side bounds, sidesteps & COD would be to include unanticipated cutting drills that would be faced in game situations.
If you would like any assistance with your training, please come and chat with our qualified instructors at ANU Sport.
Fitness Services Team