What is Runner’s Knee?
The term “runner’s knee” often refers to patellofemoral pain syndrome (PFPS). The patellofemoral joint is the joint between your knee cap (patella) and the lower part of your thigh bone (femur). Often when there is an increase in forces going through this joint, sensitivity and irritation of the joint can develop, which can sometimes cause pain.
PFPS is common in runners because of the frequency of load going through the knee joint with each step (about 2,000 steps per mile). The knee joint is very strong and typically is fully able to cope with these loads, however it may become irritated in a few scenarios:
Increase in mileage over a short period of time
Increase in hills
Increase in intensity (speed) sessions
Reduced rest/recovery days
Combination of any of these
It often boils down to doing too much too soon without adequate recovery.
Your first line of defense is Activity Modification
By modifying activity levels, a runner can almost always continue some running. The amount of running depends on how you answer the following questions:
Have you noticed a pattern in your pain?
Does it hurt mostly during longer runs? Faster runs? Hills?
How much pain do you feel during the run (on a scale of 0-10)
How long does the pain linger for after you stop running?
You should find an amount of running per week that allows for mild pain during a run (up to 4/10) and settles back down to baseline within 24 hours. Give yourself at least one day off in betweenruns initially.
Using these guidelines, you will find your starting point. Then every week or two you can gradually increase your amount of running to work towards your goal.
Since there is typically some reduction in running volume, it may be a good idea to supplement your training with cross training like cycling or swimming if these activities are pain-free.
A common mistake many runners make is to take a couple of weeks completely off running, then resume their training plan where they left off. The knee will likely feel great during the rest period, but during that time the runner has done nothing to improve the knee’s ability to tolerate the loads of running. It is much better for your rehab to reduce your running to a tolerable level, rather than stop running altogether.
Strength and Control Exercises
In addition to activity modification, you may benefit from adding in targeted strengthening exercises. The exercises given depend on the runner and the areas which may need strengthening. A qualified physiotherapist will help determine exactly which exercises would be most beneficial for you.
Generally speaking, most runners will benefit from strengthening through the quadriceps, glutes, and calf muscles. These muscles do a lot of work to manage the load of a running gait cycle, especially the lower calf muscle, which takes up to 6-8x your body weight with each step while running.
Try adding these exercises in 3×10, 3 times per week. They are simple, low load exercises which are a good place to start, especially if your knee is quite irritable. You would want to gradually increase the load and progress to more challenging exercises as your legs get stronger.
It is ok to have a little bit of pain while doing these exercises, but that pain should settle down within 1-2 hours after completing them.
Sit on the edge of a chair and tie one end of a band around your ankle and the other end around the leg of the chair.
You want to tie the band so there is no slack (or minor slack) at the beginning of the movement.
Slowly straighten out your knee fully, then slowly lower back down.
Lie on your side with both legs bent. Lift your top knee. Do not allow top hip to roll backwards.
Return to the initial position and repeat.
Stand on one foot with your heel hanging off the edge of a step. Hold on to a railing for balance. Drop your heel down as far as it can go, then raise your heel up as high as it can go.
Move slowly and controlled.
Some Thoughts on Gait Re-Training
Gait re-training can be a helpful tool in addition to activity modification and strengthening. Based on the current research, there are two running gait changes that reduce the amount of force going through the knee.
Shorter Stride. An over-stride usually means landing hard on your heel out in front of you. This could put forces up through the shin bone into the knee joint. A shorter stride means your foot should land more underneath you, which puts the force through your muscles rather than your bones and joints.
The simplest way to shorten your stride is by increasing your step rate. This means you will be taking more steps per minute at the same running pace. You would want to determine how many steps you take per minute now, then increase by 10%. For example, if your natural step rate is 160 steps per minute, you would try to increase to 176.
Monitor your “Knee Window” – When all your weight is on one leg, and the other leg is swinging forward, the amount of space between your knees is called the knee window. If your knee window is closed, there is likely more movement at your hips and more forces going through your knee joint. By thinking about keeping 1-2cm of space between your knees while running, this can help reduce these forces.
When making either or both of these gait changes, start small. Try to change one thing at a time, for 1-2 minutes at a time. Gradually increasing the amount of time spent thinking about it throughout the run. Remember, the body doesn’t like quick changes. Even if these changes are theoretically “better” technique, your body is very used to the way you have been moving your whole life. Any changes you make should be subtle and gradual to give the body time to adapt.
It cannot be stressed enough that the information and advice in this article is generalised. The best option if you are experiencing runner’s knee is to see a qualified physiotherapist for a full assessment. At Shawe Physio, we will assess to determine if runner’s knee is in fact the source of your pain and give you a structured rehab and return to running plan according to your specific needs.