In this blog, I teach you how to assess your knee pain or injury like a physical therapist!
Disclaimer
Keep in mind that this blog isn’t meant to replace a consultation with a physical therapist or medical doctor, but the information I’m going to present can help you understand the “why” behind a healthcare provider’s thought process and serve as a guide for your own rehab.
Orthopedic Examination
Since it’s beyond the scope of this blog, I won’t be reviewing certain aspects of the orthopedic examination, such as special tests, palpation, etc. If you want to learn about specific diagnoses, we have blogs covering most conditions of the knee. We also have a blog titled, “Why Your Knee Hurts (And What To Do About It!).”
With that out of the way, let’s get into it!
Observation & Movement Analysis
An evaluation usually begins as soon as you walk in the door with what I’ll describe as observation and movement analysis. I want to see how you move naturally before the “official” examination begins and you’re aware that you have a pair of eyes on you.
Are you in pain? Are you limping? How’s your range of motion? Is there noticeable swelling or muscle atrophy?
This will extend into the actual examination with daily activities, like walking, squatting, and ascending and descending stairs. If appropriate, you might even be asked to perform a single leg squat. These movements are typically assessed from multiple angles.
A misconception here is how much slight deviations from “normal” matter.
For example, it’s probably not a big deal if your single leg squat looks a little wonky. It might be your first time ever performing the movement. It might be painful. You might be fearful.
I’m just interested in how you choose to perform the movement, gathering insight into what you’re thinking and how you’re feeling, and looking for major asymmetries or differences that may influence what I examine further in terms of strength, range of motion, etc.
Perhaps unsurprisingly, one of the most important movements to look at here is the one that hurts the most or is the most bothersome to gain a better understanding of where it hurts, when it hurts, how much it hurts, and to determine if there are any simple modifications that can alleviate symptoms.
Balance
Although it’s not always necessary, examining your balance can be a component of this part of the assessment, even if it’s just single leg balance for 30 to 60 seconds.
For a more athletic individual, the Y-Balance test can be used to evaluate dynamic balance. Essentially, you’re standing on one leg and reaching as far as you can in the 3 directions of a “Y” and measuring any side-to-side differences between legs.
Knee Range of Motion
While the previous sections may vary between clinicians, examining knee range of motion is standard practice. Physical therapists use a tool called a goniometer to measure range of motion, but the phone in your hand can accomplish the task equally well.
For knee extension, lie on a flat, firm surface like the floor rather than your bed or couch. With your toes facing up toward the ceiling, squeeze your thigh muscles while aiming to press the back of your knee into the ground.
If you take a picture or video at eye level from the side, you can draw a line from the middle of your hip to your knee to your ankle.
If the knee is perfectly straight, that’s considered full knee extension.
Hyperextension can be visualized if your heel lifts off the floor when contracting your quads or by adding a prop under your foot like a rolled up towel.
For knee flexion, simply bend your knee as much as possible.
You can use your hands or a strap to provide overpressure, if tolerable and desired.
Once again, you can draw a line from the middle of your hip to your knee to your ankle or you can simply measure the distance between your heel and your butt.
For both knee extension and knee flexion, you’d perform the measurements on both sides and compare.
This is true for all of the recommendations in this blog and it’s usually best to start with the uninjured side.
Let’s move on to strength.
Knee Extension Strength
Physical therapists can assess knee extension strength with the use of an isokinetic dynamometer, handheld dynamometer, or in-line dynamometer. Manual muscle testing, which is external resistance applied by the hands, is not a valid or reliable measure of strength unless extreme weakness is present, perhaps due to a neurological condition.
The best way to measure knee extension strength on your own is with the use of a leg extension machine.
There are 2 ways to do this:
- Pick a weight and perform as many repetitions as possible on each leg. Then compare side-to-side. For example, maybe you can perform 100 pounds for 17 repetitions on your right leg but only 11 repetitions at the same weight on your left leg.
- Test your 10 rep max, 5 rep max, or any rep max you want to choose. In this example, keep increasing the weight until you can just perform the number of repetitions you picked. For instance, maybe you can perform 150 pounds for 10 reps on your right leg but only 105 pounds for 10 reps on your left leg.
You can also do both on different days. There’s not necessarily a best option.
I know many individuals will argue that the leg extension machine is not “functional,” but it’s actually the most functional way to test knee extension strength. Exercises like single leg squats, split squats, and lateral step downs are good and I’ll review them shortly, but there are more variables that may lead to noticeable asymmetries. Examples include balance, skill, confidence, and the strength and range of motion of multiple joints.
Also, in the presence of pain or swelling, such as after an injury or surgery, the body becomes good at compensating. It’s hard to cheat leg extensions and if a deficit is present, it will carry over to those other movements, as well as running and jumping.
Knee Flexion Strength
Physical therapists can assess knee flexion strength with the use of an isokinetic dynamometer, handheld dynamometer, in-line dynamometer, NordBord, or similar device.
The best way to test knee flexion strength on your own is with the use of a seated or prone hamstring curl machine.
If you don’t have access to these machines, that’s okay. The next section discusses compound movements and alternatives.
Compound Strength
There’s no shortage of exercises to choose from. Examples include single leg squats, lateral step downs, split squats, single leg bridges, single leg RDLs, and single leg hamstring sliders.
Depending on your strength, symptoms, and skill level, you can test these movements with or without weight. If you’re just using your bodyweight, you would perform as many repetitions as possible. If you’re using weight, you can choose either method I presented earlier.
The most important thing when testing and retesting exercises is consistency. For that reason, you want to try to normalize the range of motion to the best of your ability. For instance, if you perform single leg squats, your range of motion might differ with each repetition, especially as you approach failure. To combat this, you can tap your butt to a box or bench so the range of motion is the same every time.
You can also choose to perform isometrics for any of these movements. For example, you could hold a split squat with your knee hovering just above the ground for time until you fatigue. Once again, consistency (between legs and between sessions) is important so it might be helpful to film yourself performing these exercises.
Single leg-focused exercises are beneficial for comparing side-to-side differences, but they might not be realistic for all individuals based on their symptoms or function. That’s okay. You can literally choose ANY exercise. At the start of rehab, it’s just helpful to have some sort of baseline. This means you can test sit-to-stands, bodyweight squats, wall sits, hamstring curls on a ball, etc.
Nothing is off limits because your tests become your training and your training becomes your tests.
If you start performing rehab 3-5 days per week, you gradually gain a better understanding of where you’re still struggling, where you’re improving, and where you need to spend more time.
Jumping & Landing
To assess your jumping and landing abilities, physical therapists may use force plates or some other tracking system. However, there are less sophisticated ways for you to do this as well. The goal is to always be as objective as possible, but it’s not always possible and oftentimes “good enough” is better than striving for perfection.
To be honest, sometimes people get carried away with how much data they’re tracking. It’s data for the sake of data, but a lot of it might not even be relevant. So, it’s okay to keep things simple if necessary.
3 commonly used horizontal hop tests are the:
- Single Leg Hop for Distance
- Triple Hop for Distance
- Crossover Hop for Distance
For the single leg hop, you’re assessing how far you can jump in one go.
For the triple hop, you’re seeing how far you can get with 3 continuous hops.
For the crossover hop, you’re doing the same but leaping back and forth over a midline.
There’s also a 6 Meter Timed Hop Test that assesses how quickly you can hop across a fixed distance.
For all of these tests, do you measure heel-to-heel, heel-to-toe, or toe-to-toe? It doesn’t really matter as long as you’re consistent.
Should you keep your hands on your hips or not? You can do either or you can test both. It only matters if you’re comparing yourself to referenced standards from the research or data from a specific study. Otherwise, you’re your own comparison over time.
The Side Hop Test assesses how many times you can jump back and forth over a distance of 40 centimeters in 30 seconds.
For vertical tests, you can do a:
- Drop Vertical Landing
- Drop Vertical Jump
- Counter Movement Jump
These can be completed double leg or single leg, and the drop vertical jump and landing tests can be done with boxes of varying heights.
For all of these tests, I recommend filming yourself from the front and the side so you can evaluate side-to-side differences in technique, distance, height, etc. You’ll also be able to get a subjective feel of how confident or powerful you are with each movement.
Hip & Ankle Range of Motion and Strength
Something that is drilled into the head of every physical therapist during their schooling is to assess the joints above and below the location of pain. In this case, the hip and ankle.
For the ankle, you can test single leg heel raises on the floor or a step, with or without weight.
You can also use a heel raise machine, with the knees bent or straight.
The knee-to-wall test is commonly used to assess ankle dorsiflexion range of motion.
For hip range of motion and strength, you can compare internal rotation, external rotation, flexion, extension, abduction, and adduction.
The compound movements and jumping tests previously described will also assess aspects of the hips and ankles.
Rehab Goals
With all of this information in mind, I need to be clear about several points:
- I didn’t cover every possible test.
- Tests won’t necessarily be performed in this order.
- All of these tests aren’t performed in a single day.
- Not every test will be used for every single person.
- I didn’t provide specific numbers because it’s just too variable with a broad audience using different equipment.
Rehab is an ever-evolving process. As I mentioned earlier, your assessments become your training and your training becomes your assessments. There’s a natural feedback loop built in. You’re comparing your current self to your previous self with the intention of creating a better future self. Your goal is to improve deficits in strength, range of motion, power, etc., but also to improve aspects of yourself that are harder to quantify, such as your confidence and resilience.
One of the most important yet frustrating facts of rehab to know is that there’s rarely a perfect linear correlation between an improvement in function and an improvement in symptoms. It’s an imperfect process.
There might be days or weeks that you get stronger, but your symptoms remain the same. Similarly, there may be times when you don’t see any objective measures of progress, but your symptoms improve.
Unfortunately, rehab is complex and oftentimes unpredictable. It’s part of the reason why you shouldn’t “major in the minors.” What I mean by that is that you don’t have to stress about every minor difference between your knees or your legs. Social media will have you thinking that your 2 degree difference in big toe extension is why your glutes are weak and your knee hurts, but in most cases, you’re better off focusing on the basics and big picture items.
Lifestyle Considerations
Rehab is also often more than just considering what’s happening at or around your knee. Your body is an entire ecosystem that is affected by your nutrition, alcohol intake, stress, sleep, smoking habits, and so on. Obviously this is more important in certain scenarios than others, but it’s almost always worth reflecting on for managing current problems and trying to prevent future ones.
Do you want a structured plan that’s going to provide you with the knowledge and tools to feel more confident, capable, and resilient than ever before?
Check out our coaching and consultation services!
Want to learn more? Check out some of our other similar blogs:
Why Your Knee Hurts, Patellar Tendinopathy, Patellofemoral Pain, Knee Osteoarthritis
Thanks for reading. Check out the video and please leave any questions or comments below.
