Exercises and Drills for ACL Injury Prevention

The Anterior Cruciate Ligament, or ACL for short, is a ligament that is commonly injured while participating in sports such as basketball, soccer, volleyball, and skiing. Any activity that involves jumping, turning, quick stops, changes in directions or overextending the knee can injure the ACL. Recovery is possible, but prevention is preferable.
An ACL injury may range from a sprain to a complete rupture of the ligament.  People commonly refer to the worst-case scenario as ruptured, “blown-out,” or torn ACL.  Twenty years ago, this was assuredly one of the most devastating knee injuries someone could suffer.  It almost always ended their formal athletic careers and forced many people to assume a sedentary lifestyle.   Fortunately with new surgical techniques and Physical Therapy rehabilitation protocols, the devastating impact of these injuries is usually for relatively short period of time.  Most athletes and others who suffer an ACL injury are able to return to their pre-injury lifestyle by following a proper rehabilitation program and working hard.

ACL Injury Prevention

Females face a greater risk for ACL injuries due to their physical anatomy. 70% of these females suffer injuries as a result of a non-contact event.  Some of these injuries may have been prevented if the athlete had gone through an extensive ACL injury prevention program.

While preventative programs cannot change the anatomy (notch size, Tibial plateau angle, and ligament laxity) of the female athlete, they can help reduce ACL injuries by improving neuromuscular education, muscular imbalance, flexibility and overall conditioning. ACL injury prevention programs use drills, exercises and proper techniques to address aspects such as strength, balance, proprioception and endurance.  When completed consistently, these programs have been very successful at reducing the incidence of ACL injuries.

While beneficial to both sexes, females demonstrate the greatest benefits.  There are significant differences between males and females regarding the musculoskeletal system and how the body works as puberty occurs.    The post pubescent female demonstrates lower peak power in the quadriceps, lower vertical jump height and higher ground reaction forces when they land. Females have a significant amount of internal rotation of the femur and an increased valgus (“knock-kneed”) moment at the knee when they land.  They utilize the quadriceps significantly more compared to males.  This leads to less knee and hip flexion when hitting the ground after a jump and results in less hamstring muscle activity.  Hamstrings help the ACL prevent anterior (forward) translation of the femur on the Tibial plateau.

If the legs are stiff when landing, the athlete may experience a hyperextension of the knee.   Females tend to land on the same leg when they come down from a jump and if the opposite leg is used to land it is more susceptible to injury.  Young athletes are consistently deficient in core control and strength.  This leads to poor muscle control distally and can compromise the dynamic support of the lower extremity.

Drills and Exercises for Preventing ACL Injuries

ACL Injury prevention programs consist of various exercises and drills that begin to “prepare” the lower extremity for the rigors of athletic competition.  These drills help to stimulate the neuromuscular development in the athlete. A well-designed injury prevention program also tends to help athletes improve performance in their specific sport.  A well-designed program will help the athletes learn and develop proper form while addressing strength, endurance and neuromuscular (proprioception and kinesthetic awareness) deficits throughout the core and lower extremities.

The drills require verbal and visual cues to aid the athlete in proper form.  The lower extremity must remain in proper alignment to help prevent excessive sheer force on the ACL.  Many of the drills and activities focus on eccentric loading of the lower extremity musculature.  Most injuries occur when the athlete is attempting to deccelerate their body mass, and the muscles perform eccentric contractions to accomplish this task.  Plyometric training is a form of resistive exercises and drills that accentuate the eccentric contraction force of the involved muscles.  Plyometric exercises utilize the elastic properties of the muscle to help generate force.  These drills help to train the neuromuscular response of the muscle to be better prepared to provide dynamic stability to the joint.

There are hundreds of drills and exercises that can be used as part of an ACL injury prevention program.  The following are a few suggestions.

CORE:

• Planks and side planks
• Theraball planks
• Theraball roll outs
• Seated medicine ball rotations
• Standing medicine ball rotations

HIPS AND LEGS:

• Side shuffle with theraband/tubing around ankles
• Clam exercise routine
• Squats with knees in alignment with ASIS and Toes (Eliminate valgus moment at the knee.  A ball can be placed between the knees)
• Lunges
• Side lunges
• Lunges onto a Bosu ball
• Bosu ball squats
• Step ups
• Walking lunges
• Leg press

All hip and leg exercises are performed with the knees in proper alignment.   The elimination of an excess valgus moment at the knee during weight-bearing knee flexion reduces the stress on the ACL.

AGILITIES AND PLYOMETRICS:

• Carioca (Grapevine) run
• Defensive slides
• Shuttle run
• High knee jog
• Stiff knee (Band Major) run
• Two legged hop
• Single leg hop
• Box jump up/down
• Angle jumps
• Standing broad jump

All jumps are completed in sets of 10 reps or for a specific distance.  Upon landing, the knees should bend and remain in proper alignment.

ACL injury prevention programs have proven to be effective at reducing the frequency of ACL ruptures in athletes, especially female athletes.  The program can be initiated by your Physical Therapist and consistent participation will ensure a positive outcome.