Preventing Knee Injuries

For those lucky enough not to have suffered an ACL tear, or an MCL/LCL tear for that matter, now is a great time to take steps to prevent knee injuries occurring. Bear in mind that while my injury was caused by contact, non-contact mechanisms account for 70-80% of ACL injuries. Also, women are far more susceptible to ACL injuries than men, and are likely to incur injury on average 5 years earlier than a man, with the majority of injuries to women occurring between the ages of 15 and 25. Preventing knee injuries with knee strengthening exercises should be a focus for all, not just the athletically active.

So why are women more likely than men to incur ACL injuries? Partly the reasons are due to the differences in anatomy. For example, women have a wider pelvis which combined with a general lower muscle strength and a shorter ACL makes women more susceptible to ACL tears. These anatomical differences mean that women are more vulnerable to certain movements such as jumping and landing that typically lead to ACL injury. Many PT practices within local Health Centers are now offering courses to help women learn how to jump and land in an ACL-friendly way.

Women can mitigate these anatomical traits and prevent knee injuries occurring by exercising to increase knee strength. Agility drills and plyometrics should be incorporated in exercise regimes. Leg presses, squats and lunges are good for strengthening the knee and hamstrings. Muscle control exercises that train use of the hamstrings instead of the quads are also important for women. OKC (open-kinetic chain) exercises are one such exercise.

A word on OKC and CKC (closed-kinetic chain) exercises. Firstly, this section is about preventing knee injuries, not about ACL surgery recovery. This is really important because there is a medical school of thought that OKC exercises should be avoided immediately post surgery and that the bio-mechanical environment of the healing graft is optimized by prescribing CKC exercises early in rehabilitation and avoiding OKC exercises.

OKC exercises occur when the foot is not in contact with the floor. In this scenario, only the muscles around the knee are used. An example of an OKC exercise for the hamstring (isolated from the quad muscle) is cycling one-legged on an upright bicycle in the gym. As always care should be taken not to overstress the hamstring when doing this. CKC exercises are those in which the foot is in contact with a solid surface. The foot is opposed by a ground reaction force, which is transmitted to all of the joints in the lower extremity. Muscles spanning all of the joints of the lower extremity are, therefore, used. Examples of CKC exercises are the squat, leg press, and lunge.

The focus of training to prevent knee injuries is SBCE (strength, balance, core and explosive movement.)

Strong knees keep the knee joint, ligaments and cartilage protected and healthy and typical exercises to help with strength include squats and lunges.

Balance is often overlooked in a fitness regime but is extremely important in creating strong and healthy knees. Single leg balance exercises or the use of a rocker board are both great ways to easily introduce balance into a fitness program. In doing so this will also have attendant benefits on the health of the ankle, hip and lower back.

The core is also important in preventing knee exercises. In a person with a weak core, the lower body compensates during a simple movement such as walking which can force the body out of alignment. Commonly, the pelvis will drop, the hip will move out and the knee will move in. This compensation ends up putting greater stress on the knee which will lead to further knee injury and pain. A strong abdominal area will enable good strength and body alignment.

Finally, the ability to move explosively is important. The explosion may be small when we start to walk (but it is there all the same) but it is large when we play sports. Knee strengthening exercises need to support this need and the exercises themselves are similar to regular knee strengthening exercises but, obviously, are more explosive in nature. Star jumps are a great example of an exercise to support explosive movement training.