health and performance centre in motion newsletter

ACL Injuries Anterior Cruciate Ligament (ACL)

The Anterior Cruciate Ligament (ACL) is one of the ligaments that is found in

the knee. It is commonly injured with hyperextension of the knee or by twist-

ing the knee while the foot is planted. Women are at higher risk of ACL in-

jury than men due to the difference in the hip and the knee angles. Identify-

ing specific sports where the knee is at risk is the one of the first ways to

prevent injuries.

High Risk Sports:

• Soccer, Basketball, Volleyball, Skiing, Football

• Any sport that has increased knee contact, pivoting, jumping or uneven hard landing surfaces.

John T. Powell Building � University of Guelph � Guelph, ON � N1G 2W1

Phone: 519-767-5011 � Email: hpc@uoguelph.ca � www.uoguelph.ca/hpc

To Brace or Not to Brace?

The literature on bracing is quite controversial. Braces are usually only used after an ACL injury has already

occurred. The severity of the injury and where the patient is in their rehabilitation program both greatly affect

how helpful a brace will be – if at all.

Just because you have had a knee injury, does not mean you necessarily need a brace. The best way to deter-

mine this is to talk to your physiotherapist, athletic therapist or sports-medicine physician to determine if a brace

is right for you.

Importance of a quality warm-up/cool down

Warm-up:

Warm-ups are crucial to injury prevention of your ACL and all muscles, liga-

ments and tendons. It should loosen and warm muscles and prepare you for

activity. This might include slow to moderate jogging, moderate shuttle run-

ning and backward running.

Photo taken from: www.nlm.nih.gov/.../ency/imagepages/8717.htm

Cool-down: It is important to lower your heart rate and body temperature slowly after exercising. It allows the muscles to lengthen and helps prevent stiffness. It is similar to the warm-up, and involves a slow jog and stretching (as outlined in the warm-up). All of the above exercises will help with proprioception.

health and performance centre in motion newsletter

ACL Injury Prevention

John T. Powell Building � University of Guelph � Guelph, ON � N1G 2W1

Phone: 519-767-5011 � Email: hpc@uoguelph.ca � www.uoguelph.ca/hpc

John T. Powell Building � University of Guelph � Guelph, ON � N1G 2W1

Phone: 519-767-5011 � Email: hpc@uoguelph.ca � www.uoguelph.ca/hpc

ACL injury prevention involves: stretching and maintaining proper range of motion of the knee joint;

strengthening involving specific jumping or plyometric exercises; agility training; proprioception

or balance training; and proper warm-up and cool-down (see page 1).

Stretching:

Muscles should be warmed up before stretching to get the maximum benefit. Stretching can increase a joint’s

range of motion, reduce joint stiffness and it can decrease recovery time following your workout. Remember:

• Do not bounce and jerk when stretching.

• Only stretch to a point of tension and where you can hold the position with relaxed breathing.

• Hold each stretch for at least 30 seconds and ensure there is tension continuously.

Strengthening:

ACL injuries often occur when people that have a weak hamstring muscle (back of the thigh) compared to their

quadriceps muscle (front of the thigh). Strengthening can help address the strength difference between the mus-

cles. Choosing the position to strengthen is also important when preventing and rehabilitating the ACL injured

knee. Training the muscle in a weight bearing position (both feet on the ground) typi-

cally leads to improved function in activities of daily living, recreation and sport.

Plyometrics:

These exercises will help you learn how to land with control from a jump. It is impor-

tant to absorb the landing initially on the balls of your feet and then rocking back to the

heels of your feet. You should finish with your weight evenly distributed across your

foot. Your knees should be bent and in line with your foot position. These exercise

increase your strength and joint awareness and help you avoid positions that misalign

your knees and stress your ACL. Some examples of plyometric exercises are: side to

side and forward and back hops over a cone, alternate lunging and vertical jumping,

all emphasizing the best alignment of knees and your feet on the landing.

Agility training:

This type of training helps increase stability of the hip, ankle and knee as a unit. The

quickness of the exercises also increases your neuromuscular awareness or control.

This includes: quick running forward and backward, diagonal (pivoting) and grapevine

running.