Anterior Cruciate Ligament Information What Coaches Should Know

Symptoms of ACL injury

  • Athlete may feel or hear a pop or crack at the time of injury
  • Extreme pain immediately after injury
  • Swelling of the knee within minutes to hours after injury
  • A feeling of instability (i.e. feels like knee will buckle, "give out" or "give way") when trying to stand

Signs of ACL injury

  • Widespread tenderness of knee
  • Swelling by the next week
  • Black or blue discoloration around knee

What to do?

  • Immediately discontinue athlete from play
  • RICE
    • R – Rest the joint
    • I – Ice to reduce swelling
    • C – Compression
    • E – Elevation
  • Seek medical attention as soon as possible

Anterior Cruciate ligament (ACL) is the fibrous band that attaches the thigh bone & shin bone in the knee joint and provides stability to the knee. ACL injury is a common concern among athletes and coaches because it can keep the athlete out of play for rest of the season and usually requires surgery. On average, athletes are eight times more likely to suffer ACL injuries in competition than practice. Girls have eight times higher chance of ACL injury than boys.

ACL injury has a higher incidence in football players (41%) compared to other sports (Girl’s soccer – 19%, Girls’ basketball: 13%, Boys’ soccer – 9%).

Mechanism of Injury

The mechanism leading to ACL injury varies by sport.  Knowing these mechanisms can help coaches and athletic trainers develop targeted preventive interventions.

  • A sudden stop, twist, pivot or change in direction at the knee joint — twisting force to the knee while foot is firmly planted on the ground (improper cutting)
  • Extreme hyperextension of the knee — improper landing
  • Direct contact — improper sideway tackle

After an injury to the knee while playing in a football game, look for the above signs & symptoms. Treatment depends on a number of factors (athlete’s age, life style, sporting involvement, phase of season, degree of knee instability, and other associated injuries). Surgery is performed more often than not in cases of ACL tears.

Who requires surgery?

The younger and more sports active an individual is, the more likely they will continue to injure their knee unless the ACL is repaired or replaced.  Any athlete wishing to continue sports that require running, jumping and twisting should be considered a surgical candidate.

What if the athlete is still growing?

Unfortunately ACL injuries occur even in the young and growing athlete.  The “growth centers” in these athletes are still active and can be injured either by the injury causing the torn ACL and/or by ill-planned surgery. 

If the injury is ignored, the young athlete will more than likely suffer serious injuries to his/her knee based on sports participation, as well as normal outside play activities.

How long will the athlete with a repaired ACL be out of playing the sport? – It varies with different scenarios but, in most cases it takes 6 – 9 months after surgery to return to full competition.


Coaches and athletic trainers working with high school athletes should practice targeted preventive measures to reduce the risk of ACL injuries. These measures could include some of the following:

  • Active Warm-up
  • Power and Stability / Eccentric Strength — landing
  • Strength Development
  • Change of Direction Concepts — learning how to stop
  • Change of Direction Conditioning
  • Wearing comfortable shoes with specific cleats
  • Proper landing techniques with knees flexed and feet wide apart

ACL injury prevention training program

  • Warm up — jog line-to-line, backward running, shuttle run
  • Stretching — Calf, quadriceps, hamstrings, inner thigh, hip flexors
  • Neuromuscular training
  • Strengthening — walking lunges, single – toe raising, Russian hamstrings
  • Plyometric training — jump training program: Lateral hops, forward hops, single leg jump etc.
  • Plant/landing skill
  • Proprioception — Single leg stance, balance mat, anterior & posterior step-up

Injury Prevention news & articles

More articles