CrossFit for Knee Stability


As a CrossFit athlete, your knees are one of your most important assets. Treat them kindly, and they will reward you with safe and skillful performance. On the other hand, burden them with useless exercises and they will fail to support you when you need them. Fortunately, despite the intensity of some of the CrossFit leg exercises, many are just what your doctor,  as well as your physiotherapist ordered for safe and functional knees.

Your Knee Muscle Support Team

A knee strengthening workout programme must actively engage your hamstrings, quadriceps, adductors or medial leg muscles, and abductors or lateral leg muscles. Your hamstrings flex your knees, while your quadriceps extend them. Meanwhile, your adductors move your leg toward the center of your body, and your abductors move your leg away from your midline.

Whilst these muscle groups can indeed perform isolated actions, they work best when they move as a coordinated unit. Exercises that target more than one muscle group simultaneously are referred to as compound exercises. Adding the barbell, medicine ball, kettlebells or any other type of CrossFit equipment to these exercises increases their efficiency and effectiveness.

The Importance of Compression Forces

Most compound exercises fall into the closed kinetic chain category. Common CrossFit examples include dead lifts, power cleans, squats and lunges. These exercises actively engage your hamstrings, quads and glutes. Meanwhile your abductor and adductors are standing by and acting as trusted knee stabilizers.

The term closed kinetic chain implies that your thigh bone or femur is moving upon a stable shin bone or tibia, whilst your feet remain in a fixed position on the ground or on a platform. Closed chain exercises create joint compression forces, which enhance joint stability and help you maintain the correct knee alignment. In contrast, open chain exercises such as the leg extension machine create shearing forces, which de-stabilize your knees. Just in case you were wondering why the extension machine has no place in the CrossFit workout.

Closed Chain Exercise Examples

Adding the barbell to your squat and lunge routine –either by  holding it across your chest or resting it in your shoulders– increases compression forces and contributes to knee stability. Use a medicine ball or kettlebell with these exercises, and you add additional agility and power training. Include exercises such as the body bar dead lift, which targets the hamstrings, and the plie squat, which works your adductors. These exercises help your knees maintain proper alignment and protect you from serious injuries.

CrossFit and the Unhappy Triad

No, the unhappy triad is not one of the options featured on a Chinese restaurant menu. The term refers to an injury pattern that includes a simultaneous tear of your ACL, MCL and medial meniscus. Unfortunately, female CrossFit athletes are often vulnerable to this injury syndrome, often due to weak hamstrings and/or adductor muscles.

Identifying Weaknesses

The manner in which you perform certain CrossFit exercises gives clues about muscle weaknesses and imbalances. Objectivity is challenging whilst you are performing the exercise, either because you are too busy negotiating the pain, or your local CrossFit box does not have any mirrors. If you suspect that your knee alignment or stability might be a bit off, book an appointment with one of our physiotherapists, and ask him or her to watch you perform one of your WOD’s. The insights will no doubt be enlightening.

Call us today for expert Physiotherapy at Happy Physio on (08) 9272 7359!