ACL Injuries

From the WebMD Archives

By Amy McGorry

Some Olympic athletes headed home from Sochi sporting medals, while others were sporting knee braces due to anterior cruciate ligament (ACL) injuries. This “mother of all injuries” usually knocks athletes out for the season, since it typically involves a six- to nine-month recovery process.

While hard hits and falls while skiing can cause ACL tears, they usually occur without contact, such as when an athlete makes an awkward landing or pivots on a planted foot. (The injuries are common in football, basketball, lacrosse and soccer.) Training the leg muscles to fire properly -- and having good form -- can help keep ACL injuries from sidelining you.

When The ACL Is A Pain

The ACL is a band in the knee that connects the thighbone (femur) to the shinbone (tibia). It helps stabilize the knee and controls rotation of the leg.

Studies show that the ACL is under more stress when the knee is straight or bent five to 20 degrees. An inwardly directed force (think “knocked-knee position”) also stresses the ACL. If the force exceeds the strength of the ligament, a tear can occur. Athletes will often complain of a “popping,” followed by pain and swelling. The knee loses stability, and the resulting grinding and excessive motions can cause wear and tear on the joint and surrounding soft tissues.

Why You're Sidelined

It’s like the perfect storm when an ACL injury occurs: A few factors simultaneously combine to wipe an athlete out for a season. (Imagine that you're rebounding in basketball, and you land with your knee straight. Add weak buttocks and weak hamstrings that aren’t efficiently supporting the ACL, and... pop!)

Players participating in sports involving sudden stops, jumps and pivoting motions are most at risk for ACL injuries. Muscle imbalances and poor form are partly to blame. Gender even plays a role: Experts say female athletes are six to eight times more at risk, compared to males -- possibly due to hip/knee alignment issues, hormone levels or delayed hamstring firing.

How To Stay In The Game

Form: our favorite four-letter word! Having proper form (and awareness of the knee and foot relationship) while you play your sport is crucial. Strong, flexible glutes, hamstrings, quadriceps and core are important, too.


Try these exercises:

Side Shuffles

  • Start standing with slightly bent knees
  • Push off with left foot and step to the side with the right foot
  • Keep the hip/knee/ankle in a straight line
  • Don’t let knee cave in or out
  • Do one minute in each direction

Hamstring Curl

  • Lie on your back, hands at side, feet on physioball
  • Lift hips and buttocks toward ceiling, digging heels into the ball
  • Bend knees and roll ball and feet towards buttocks
  • Straighten knees slowly, keeping them in line as you roll the ball out
  • 3 sets of 10 repetitions


  • Start in lunge position, right leg forward with knee over ankle
  • Push off from your right foot and bring your left leg forward into lunge position
  • Don’t let knee roll in or out and keep it in line with the ankle
  • As you land, accept weight on ball of your foot with the knee slightly bent
  • 3 sets of 10 repetitions

Sidelying Lift

  • Lie on side with your hips stacked
  • Lift your top leg up without letting it come forward
  • Slowly lower
  • 3 sets of 10 repetitions

Always check with a physician prior to starting any exercise program.

WebMD Feature from Turner Broadcasting System
© Turner Broadcasting System, Inc.


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