The ACL and its friends

It’s seven o’clock in the morning and Anna is already awake. Today is an important day. If they win todays basketball game they will go to the finals.

She is nervous and she can’t sit still and it feels like her muscles, ligaments and joints are living their own life, like they are talking to each other and she is right…

The brain, also called the coach, sends out signals to the muscles and joints to wake up.

“It is important that you help each other out today and work together as a team.”

The muscles start to wake up slowly. They are well prepared for the game today. They have improved their strength by training on the new machines at the gym.

“I will do my best”, says the tired and pronated foot, “but I can’t promise anything.”

“What do you mean by you can’t promise anything”?” says Tibialis posterior muscle in an angry voice. “The team and I always have to compensate when you collapse as soon as you hit the ground.”

The game is now playing at full power. The muscles and ligaments are working hard. Even the tired foot is doing its best.

They are four under and it is two minutes to go. Anna has nothing to loose and is working very hard. She is running with the ball and suddenly something happens. Anna gets pushed from the side. She falls and her right knee starts to pivot.

The proprioceptors of the anterior cruciate ligament, ACL, send out signals to the muscles and the coach, the brain. 

“You have to help me to decelerate the tibia that is coming forward and the pivoting of the knee. You have to work together as a team or this will not go well!”

Even the medial collateral ligament sends out signals for help. 

“We can help you”, shout the quadriceps muscles. 

They realize soon that this is much harder than they thought it would be. They have built up their strength on the machine where Anna has been sitting on her butt kicking her legs. When in basketball do you do that?

“We need help”, screams the Quadriceps. “The foot what are you doing down there?”

“I can’t take it any more, says the foot. “I’m so tired. Don’t forget that I’m born this way. That’s not my fault. This is so different from training pronation and supination with a rubberband. Soleus and Tibialis posterior can you pull the tibia back while the Tibialis posterior also decelerates pronation of the foot?”

“I’m doing my best”, says the soleus. “I’m holding on to the tibia and fibula but tibia is falling forward and rotating internally too much and too fast.”

The gastrocnemius tries to decelerate the internal rotation of femur and the eversion of the subtalar joint. They realize soon that this is so different from the heavy heel lifts that they have been doing at the gym.

“Piriformis we need help to decelerate the internal rotation of the femur!” shouts the gastrocnemius”

Piriformis is struggling hard and asks the hamstrings to decelerate the internal rotation and flexion of the knee, and also help to decelerate the valgus position of the knee.

“We are doing our best but don’t forget that we also have to decelerate the flexion of the hip. We are so confused. We have only been trained to bend the knee in an open chain position lying on the stomach. Standing up in a closed chain position we seem work totally different.”

Gluteus medius is also trying to help out by holding on to the trochanter major, trying to decelerate the adduction and internal rotation of the femur. The muscle has to work very hard because this is much harder then lying on the side lifting the leg.

“You have to work harder screams the ACL. I can’t take it much longer!!!”


It gets quite. All of them understand what just had happened and they feel very sad. They had lost their friend, the ACL. The Semimembranosis and the ACL were best friends. Together they decelerated the rotation and forward motion of the tibia. They decelerated the pivoting of the knee.

“What will happen now?” asked the sad and worried Semimembranosis.

How will I be able to compensate for this? Is it true that they might even use me as a graft?

“They can take the graft from us instead” said the quadriceps muscles.

– “What happened? What went wrong?” asked the tired pronated foot.

The coach, the brain, tries to support everyone in the team.

“You did your best and you can’t blame yourself. We need to learn from this now. We need to be more prepared. We need to find out why this happened, treat the cause and than train more functionally. That way we will know how to react when we get in to situations like this.”

Anna had an ACL surgery and the quadriceps shared of its tendon. Anna and her team had learned a big lesson.

All of the players in the team went through individual testing for mobility, stability, force speed and power.

Functional movement patterns and local motion at the foot/knee, hip, trunk and shoulder girdle complex were tested in an upright position with the help of the testing system 1080 Movement Assessment Plan (1080MAP).  

The foundation of any physical performance is to have good mobility and stability. If not, the body will find ways to compensate for it. To prevent future injuries it is really important to have good functional mobility and strength.

The 1080MAP showed that many of the players were lacking extension and rotation of the hips. Good mobility in extension and rotation of the hips is really important when it comes to change of direction and sprinting while playing basketball.

To prevent the knee from going through excessive valgus and internal rotation, putting the ACL at risk, the players who needed it, were given exercises to increase the extension and the ability to open up, external rotate, the hips.

To increase mobility and stability each player got an individual home program.

To test and train force, speed and power with the same functional movement patterns they used the 1080 Quantum.

The result showed the relationship between force and speed, which is another informative key to improve any physical performance.

By combining test results of mobility, stability, force and speed it was easy to see what each player should focus on, mobility or strength, and in what body part.

Now they trained more functional.

They trained the muscles and joints to work together, not is isolation and in three planes of motion.

They also trained with 1080 Quantum to safely and independently control resistance and speed in the concentric and eccentric phase while measuring force, speed and power throughout the movement.

To really make sure that the training improved their ability to sprint and change direction they used the 1080 Sprint to test and train.

1080 Sprint has the same robotic technology as the 1080 Quantum and has a 90 m long line that could easily be used on the basketball court. It was used for variable resistant over the course of a sprint and for overspeed training to allow for neuromuscular adaption to high speeds in a fully controlled environment.

When Anna started to play again she was quicker and better than ever before. The muscles were well prepared and knew how to react in the different positions. Anna got nominated “the best player of the year”.

The coach, the brain, was very proud. The muscles, joints and the ligaments were very happy. Now they were finally a real team. It was a lot of laughter in the team and they lived happily ever after…

Written by

Jessica Parnevik-Muth