Welcome to my first of many posts that revolve around our mobility class here at CrossFit 1827 and (hopefully) educate the readers as to the function and abilities of our bodies!
The first topic I've chosen to write about is knee pain. I get a lot of people asking me to cover knees in our weekly mobility class, usually due to some sort of irritation in and around the knee. We covered some general mobilizations, stretches and exercises in class as well as some other education such as lifting advice (frequency, technique etc) in class, but for those of you who couldn't make it or are not members, hopefully this will give you a little bit of insight into treating or preventing knee pain as it is quite common amongst athletes of all backgrounds. We will (shallow) dive into some anatomy and function of the knee, types of injuries and 3 ways to treat/avoid knee pain.
The knee has 2 articulations, or joints. The first is the Tibiofemoral Joint (articulation of the Tibia and Femur). This joint allows for flexion and extension of the knee in the sagittal plane and slight internal and external rotation of the tibia in the transverse plane. The second joint is the Patellofemoral Joint. This joint is an articulation between the Patella and the Femur allowing transmission of tensile forces from quadriceps as well as increasing extension lever arm.
3 bones involved in knee joint: Tibia (shin bone), Femur (thigh bone), Patella (knee cap)
2 types of cartilage in joint: Meniscus- 2 menisci found between tibia and femur, act as a shock absorber. Also used to evenly load the joint when weight bearing. Nerves in meniscus send feedback to brain regarding proprioception. Articular cartilage: found on the end of both the tibia and femur. Helps bones move slowly over each other.
Synovial Hinge joint. Synovial means there is a fluid filled capsule to help the bones articulate. Hinge is the type of movement. Moves similar to a door hinge- one plane of motion, in this case, sagittal.
Support the body in an upright function
Propels body forward ie; gait
Along with musculature, creates movement in the leg in the sagittal plane
Types of Knee Injuries:
Overuse injuries: Rule of “Too”: Too long, too heavy, too often.
This type of injury is most commonplace amongst gym-goers. We tend to want to see results fast. This leads us to spend more time in the gym doing more sets and reps with heavier loads and less movement variability than our tissues can adapt comfortably to. Our bodies will show signs of this before pain, but we need to listen! Watch for tightness, weakness and/or instability not only at the knee, but joints above and below the knees such as hips and ankles. Listening to these signs may keep us from experiencing this unpleasant pain.
These injuries occur when receiving force from an external source, usually in a closed chain position like standing. For example, your 100# dog runs into the side of your leg and sprains your ACL. Now this may seem like an injury that is unpreventable, but strengthening the knee, developing motor control and working in different planes of motion will allow you to receive more external forces without injury.
3 Ways to Get/Keep Your Knees Healthy
Bodyweight. Knees have a primary function in our gait patterns. If we are to take an average of 10,000 steps/day @ 200lbs BW, that a total of 1 million lbs of bodyweight going through each individual knee per day. That doesn’t even account for the increase of force that occurs with inclines, stairs, external load etc. To reduce the load on the knee daily, find a comfortable bodyweight to function at. If knees are already irritated, try losing a few pounds of bodyweight to reduce the impact.
Warm Up. Wasn’t it nice when we were 10 years old and just went all out at recess with no repercussions? Now, just the thought of that all out sprint is tightening up my hamstrings. As we age, the average athlete has to spend more and more time getting ready for their fitness session. Obviously what you intend to do will play a role in how long you warm up and the type of warm up you do… Think 100m sprint vs yoga. Some Strength and Conditioning coaches recommend 2:1 workout to warm up ratio. Meaning if you spend 1hr training, your warm-up will be 30mins. This is entirely subjective based on the individual, but something to consider when dealing with/preventing knee pain.
Vary your lifts/exercises. It is important to think about your fitness goals and build your workouts to achieve them. Next, it is about realizing that those goals can be achieved many different ways. For example, if you’re looking to burn a few extra calories and think running everyday will achieve your goal, that’s fine. But is there a safer way to get the heart rate up and ease some of the forces placed on the knees? Using figure 1, you could get on a bike every other workout to reduce forces placed upon the knee by up to 14x.
Another example could be used for the squat. In CrossFit we tend to do a lot more front squats (think wall balls, front squats, cleans etc). In biomechanics, the length of the moment arms will determine which joints will bear the most load. The longer the moment arm, the more load that will be applied to the joint axis through leverage. Looking at figure 2, you can see the relationships of the bar relative to the knees and hips in two different squats. Perhaps doing a front squat every time we squat, or as frequently as everyday in the form of wallballs, is not in the best interest for our knees. If your goal is to become stronger, we can work on our squat pattern for strength in a different way that will allow us longevity. Remember, pain doesn’t necessarily mean something is injured. It’s the bodies way of telling you it wants CHANGE!