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Got Pain? No Gains! ACL Sprain

Learn The Signs & Symptoms Of This Common Knee Injury

Posted by heyhay5212 - October 28th, 2015

The knee takes a lot stress from the body due to running, squatting, lunging, and jumping. While running and walking, a person’s knee can bear loads of three to four times their bodyweight (Anderson and Parr, 2009, p.574). The knee is also subject to a lot of torque forces because of its position between two long bones – the femur and the tibia. The anterior cruciate ligament is a critical stabilizing ligament inside the knee joint, which is prone to injury.

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The knee is made up of the tibiofemoral joint. Within the tibiofemoral joint there are several structures:

  • Menisci – Disks of fibrocartilage that are attached to the superior plateau (top) of the tibia. Within the tibiofemoral joint there are two menisci: the medial meniscus and the lateral meniscus. The functions of the menisci include absorption and dissipation of forces, increasing knee stability, and improving the congruency of the joint surfaces to evenly distribute the stress across the joint (Anderson and Parr, 2009, p. 575).  
  • Anterior Cruciate Ligament (ACL) – A stabilizer in the knee that prevents anterior translation (forward movement) of the tibia while the femur is stationary, posterior translation (backward movement) of the femur on a stationary tibia, internal and external rotation (twisting) of the tibia on the femur, and hyperextension of the tibia. The ACL is frequently injured during deceleration movements such as changing directions, planting, and cutting (Anderson and Parr, 2009, p. 579).

  • Posterior Cruciate Ligament (PCL) – The primary stabilizer that is shorter and stronger than the ACL. The PCL prevents posterior displacement (backward movement) of the tibia on a stationary femur (Anderson and Parr, 2009, p. 580).

  • Medial Collateral Ligament (MCL) – A ligament that runs across the medial (inside) aspect of the knee to prevent valgus forces (forces hitting the knee from the outside). The MCL is more commonly injured than the LCL.

  • Lateral Collateral Ligament (LCL) – A ligament that runs across the lateral (outside) aspect of the knee to prevent varus forces (forces hitting the knee from the inside).

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Types Of ACL Sprains

A sprain is an injury to a ligament in the body where a strain is an injury to a muscle. When classifying an ACL sprain, there are three different degrees (Anderson and Parr, 2009, p. 142):

  • First Degree – Few fibers of the ligament are torn. The muscles around the injury only have mild weakness with no spasm. There is mild swelling around the joint with a minor loss of function. Typically first degree sprains are described like a “tweak” to the knee and the person is able to “walk it off”. First degree sprains can typically be treated with RICE: Rest, Ice, Compression, and Elevation. The general rule of thumb is if you have pain with a certain movement after a first degree sprain, then DO NOT do it until the pain subsides. General strengthening of the knee and the hips will help the patient from re-injuring the ACL.

  • Second Degree – Nearly half of the fibers in the ligament are torn. The muscles around the joint have mild to moderate weakness and may have some minor spasms.  There is moderate to severe loss of function at the knee. The injured person may not want to move the knee or put pressure on the injured leg. Moderate swelling will occur around the joint.  Crutches may be needed so the person can move around without pain in the knee. A second degree sprain warrants a visit to the doctor to discuss the options for the best outcome for you. Some second degree sprains can heal without surgery depending on what type of activities the injured person would like to return to. If the doctor and the patient choose to forgo surgery, then the patient will typically undergo several weeks of physical therapy. Although some second degree sprains will be surgically repaired if the injured person would like to return to high levels of activity, such as competitive sports with lots of running and cutting.

  • Third Degree – The ligament is completely ruptured. The muscles around the joint have mild to moderate weakness and may have some minor spasms. Moderate to severe swelling will occur around the joint. The knee is very unstable and the patient will report the knee is “giving out”, especially if the person is turning a corner or trying to change directions while walking. Other structures in the knee can be damaged with a third degree ACL sprain, such as the MCL and/or the medial meniscus. Popping and cracking may occur within the joint after the injury. The patient should schedule an appointment with a doctor to get the knee evaluated and to see if any other structures in the knee are damaged. Once the doctor has come up with a definitive diagnosis of what structures are damaged, he/she will decide the type of surgical procedure that would be most beneficial for the patient. Third degree ACL sprains can be treated without surgery but the patient will have to make decisions about the types of activities he/she will and will not participate in. Non-surgical treatment of third degree ACL sprains typically have complications such as patellar tendonitis, arthritis, and chronic pain/swelling, and are not the preferred treatment, but the patient and the doctor will need to make the treatment decision together.  

General Treatment

As with any sprain, the patient should use the RICE method as mentioned above. Rest the joint as much as possible. Crutches may be needed to increase the amount of rest at the joint. Ice the area at least once a day after activities that are difficult or painful. Ice the knee for 20 minutes at a time, with at least 60 minutes in-between icing sessions. If the patient is functional enough to perform physical activity without pain, do not ice before activity. Save the ice until after the activity is over.

Compress the joint with an ACE wrap bandage to push out any swelling in the joint. When applying a compression wrap to the knee, start at the calf and wrap upward toward the hip. Use about 75% stretch on the compression bandage. To find 75% stretch, take the bandage and pull the bandage as tight as possible then release the bandage until the bandage is 75% of the length it was when it was pulled as tight as possible. Try to use this amount of tension when wrapping the entire joint. Be sure not to wrap too tight – do not let any numbness occur around the wrap or in the calves and feet.

Elevate the joint to help relieve pressure on the joint and to reduce swelling. When elevating the knee, it should be above the level of the heart so any excess fluid will be pulled back into circulation.

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Women are more likely to injure the ACL than men (Anderson and Parr, 2009, p. 593).  Prophylactic (preventative) bracing has not been shown to prevent ACL injuries (Anderson and Parr, 2009, p. 594). Improving strength and correcting imbalances between the hamstring and quadriceps muscles can help protect the knee from injuries. Hip strengthening of the gluteus maximus and the gluteus medius can increase stability up the kinetic chain to reduce forces at the knee. If you have any concerns about pain or problems in your knee, contact a doctor, physical therapist, athletic trainer or another qualified health care professional.


Anderson, M., & Parr, G. (2009). Shoulder Conditions. In Foundations of athletic training: Prevention, assessment, and management (4th ed.). Philadelphia, PA: Wolters Kluwer Health/Lippincott Williams & Wilkins.

NOTE: This article is intended purely for educational purposes. It is not intended to diagnose, treat, or replace advice from a qualified healthcare professional. Every person with an injury is different and needs an evaluation by a physician, physical therapist, athletic trainer, or qualified healthcare professional to identify any problems. Please consult a qualified healthcare professional if you are experiencing any of the signs and/or symptoms described.

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posted by heyhay5212
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Owner of Onyx Athletic Performance
Certified and Licensed Athletic Trainer

Certified Strength and Conditioning Specialist

BS in Athletic Training, Minor in Nutrition, University of Utah

Was It A Good Lift?

This is a topic that seems to be a rather controversial issue in the fitness community: proper range of motion (ROM) and technique...


Oh snap, I think I may have the 3rd  degree one since it's been a year and I still can't put weights on my knee. Had it checked months ago but they said it could be just swelling ..time to call a specialist.

heyhay5212  Edit  Delete  Close

Good to know! I hope you feel better soon.

aharmon22  Edit  Delete  Close

Turns out they think it's just runners knee !!


Really Insightful. Great article!


Great article @heyhay5212, you always CRUSH IT! Looking forward to the next one! :-D  Great Read!


this article for me  :d i injuried my left knee again.:) Thanks for advices

heyhay5212  Edit  Delete  Close

That's good news!  Hamstring strains are annoying but they can be fixed much more easily than a torn ACL.  Strengthen up your glutes, core muscles, and legs to keep the hamstring strain from returning.

ycaner  Edit  Delete  Close

after long time , i still pain on my hamsting tendon. but doctors said that there is nothing to fear , no muscle tear or meniscal tear  or something like that. i am really like. just i need to make it stronger.


Just an interesting sidenote to the topic: Luckily also the protesis industry has finally noticed that females do not have the same joints as males do. Unbelieveable but true up to just a little bit ago they gave women the same protesis as they did for men ;) Until they finally figured that it actually even gives them disadvantages as well as postural issues that would carry on into other joints or the spine.

heyhay5212  Edit  Delete  Close

Interesting fact! That makes a lot of sense with the female anatomy being so different with wider hips and larger Q angles at the knee. 


Great article! Learned a lot!

heyhay5212  Edit  Delete  Close

Sweet. I hope your knee is doing better!


Very nice and informative article @heyhay5212! After taking a kinesiology paper this year, I actually understood most of the information you gave :D lol

heyhay5212  Edit  Delete  Close

Sweet! I'm glad the information in the article wasn't too technical.


Excellent 2nd installment to your "Got Pain? No Gains!" series! Looking forward to the rest!

heyhay5212  Edit  Delete  Close

Thanks! I'm always looking for suggestions for my next article about injuries. Let me know if you want to see something!