ACL injury can be caused by anatomical factors (bone structure etc), hormonal factors (increased levels of the hormone ‘relaxin’ in the female body increase ligament laxity, hence the controversy over pregnant women playing netball and an increase in ACL injuries in certain stages of the menstrual cycle), environmental factors (ground friction and hardness and the use of studs or sprigs on boots) and biomechanical factors (position of body segments, muscular support of the knee and loading patterns).
It is the biomechanical factors we can modify to prevent injury.
By partaking in standard strength training, we are able to enhance the stretch reflexes of the muscles, that is, we can ensure the muscles contract to resist a negative movement before the full strain is taken by the ACL. Balance training is also effective in this respect.
Particular attention should be paid to the posterior chain (particularly the hamstring muscle group), as the hamstrings have the same effect on the tibia (shin) as the ACL. Strong hamstrings (relative to the quadriceps) will resist excessive anterior tibial translation and reduce strain on the ACL.
The worse type of exercise is machine weights, where imbalances and non-functional movements increase the chance of suffering an ACL injury.
So partake in multi-joint functional strength (focussing on the posterior chain) and balance training to reduce the chance of injury.
