Strengthen Knees for Running: Why You Should Include Co-Contractions for An Efficient Stride

When it comes to running efficiently and preventing injury, one key area often overlooked is the knee. Strengthening knees for running is crucial to enhance your performance, reduce fatigue, and protect against common injuries. One of the most effective ways to build knee strength and stability is through the concept of co-contractions—where multiple muscles around a joint work together to stabilize and create a spring-like action. By incorporating co-contractions into your strength training and warm-up routines, you can improve your stride efficiency and ensure that your knees remain protected while you run. In this article, we’ll dive into how co-contractions can help strengthen your knees for running, and why they’re essential for achieving a more powerful and injury-free stride.

What ARE Co-Contractions?

When introducing the concept of co-contractions to my Women’s Running Academy Mentees I always start with this video of Eulid Kipchog running at the 2018 London Marathon. His stride is just so damn energy efficient; it’s beautiful.

Things to note:

• Just before his foot lands, his body creates some pretensioning in the leg to put a nice bend in the knee to prepare for landing.
• The knee stays at almost the same bend from there all the way through.
• The knee does not really straighten from that angle until after toe off.

Muscles are mostly working eccentrically (as they lengthen) to slow down the opposite of their “action” so that we can store and release energy as we move. This is true the whole length of your legs, which is why it’s so important to strengthen knees for running.

Your quads are working to slow and control the bending of the knee while the hamstrings slow and control the extending of the knee. Your calves are slowing and controlling ankle dorsiflexion. The image below helps visualize this process.

This of course isn’t something we can or should think about while we are running. BUT it is something that we can practice in our strength training and with our running warm ups using: co-contractions!

How to Strengthen Knees for Running with Co-Contractions

Co-contractions are defined as the contraction of all the muscles around a joint (primarily knee and ankles here) during rapid movement to ensure necessary stiffness and spring actions around that joint.

First, they help you pre-tension the muscles around your joints to help accept the load as you run - protecting your joints and helping to store elastic energy to keep moving forward.

Second, they help you practice hip extension before knee extension - a crucial piece to getting power from your toe-off using your glutes.

Notice, on the left, my knee extends (straightens) before I stand all the way up, forcing me to extend from the back to complete the movement. While on the right, that knee stays bent the whole time allowing me to move more efficiently through hip extension. Of course, this is an exaggerated movement but we still don’t want that knee to extend before your hips in your stride. You need that hip extension to power you forward!

Want to protect your knees when you run?

Co-contractions!

Want to save your energy to run longer and harder?

Co-contractions!

Want to make your speed work feel effortless (...ok, less hard)?

Co-contractions!

Examples of Co-Contractions

Below, you’ll find some examples of co-contractions. In each of them, pay careful attention to the bend in the knee. Notice how it doesn’t change much throughout the whole movement. This may take some practice at first, so consider filming yourself or practicing in front of a mirror and closely monitor that knee bend.

The videos below help explain this process.

Slower to feel it:

Quick, because that’s how it happens when you run:

You can even load it up as part of your strength training:

“Speed is not simply generated by performing the fastest possible (concentric) muscle action, but above all by distributing the movement over as many joints as possible... Speed is thus a function of coordination” Frans Bosch

The more synchronized your hip, knee, and ankle extension are, the greater the power in each step. More return on energy investment per step means less energy needed overall!

BUT if you are already extended (APT,  flared ribs, cracked egg) your true extension actions will be limited.

Training this skill is important but won’t do much without all the strength or stack work to help you load through the middle.

Summary

The stance phase of running is a nearly isometric exercise around the knee and it is vital to strengthen knees for running with the help of co-contractions.

Co-contractions help make the process of energy storage and release more efficient.

Co-contractions train the stability needed around the knee and ankle.

Co-contractions help practice hip extension before knee extension, which helps with efficient toe-off, lets the glutes do their job, and protects the knee.

Co-Contractions help prevent “energy leaks” and protect our joints!

Next On Your Reading List:

Unlocking Peak Performance: Exploring the Five Skills Framework for Efficient Running

Strength Training for Runners at Home. How to Get Results!

Muscle Imbalance in Your Legs: Symptoms of an Inefficient Running Stride