How I Stopped Guessing With My Knee Rehab

After my knee MRI showed a cartilage and bone injury, the question wasn’t just:

What exercises should I do to strengthen my knee?

It became: What does this exercise actually load?

That shift changed the way I approached my rehab.

Because when you are dealing with a cartilage or bone-related knee injury, not all exercises are equal. Two exercises may both look like “quad strengthening”, but they can load the knee in very different ways.

Some exercises create more compression through the patellofemoral joint. Some bias the medial or lateral compartment more. Some load the knee more in certain ranges of flexion. Some are fine during the session but create a delayed response later that shows up as swelling, stiffness or loss of range.

So instead of just asking whether an exercise hurt, I started asking a better question:

Where is this load going?

Cartilage Rehab Is Not Just About Load

A common mistake in rehab is thinking only in terms of how hard an exercise is.

Easy exercise. Hard exercise. Low load. High load.

That matters, but it is not the full picture.

With a cartilage and bone injury, I also had to think about location.

A squat, lunge, stair, hop and run do not all load the same part of the knee in the same way. The same exercise can also change depending on depth, speed, step height, trunk position, external load and whether it is performed on one leg or two.

For me, this became particularly relevant once I looked at where my lesion appeared to sit on MRI.

Seedhom’s research suggests that many patellofemoral cartilage lesions occur where the patella and femur contact around 40 to 80 degrees of knee flexion. Interestingly, this also appeared to line up with the zone my lesion was located in on MRI.

That did not mean I had to avoid that range forever.

But it did mean I had to respect it early.

Why Mid-Range Knee Flexion Mattered

Early on, the movements I had to be most careful with were not necessarily the ones that looked the most dramatic.

It was things like:

• Stairs

• Step-downs

• Lunges

• Split squats

• Loaded work around 45 to 75 degrees of knee bend

These were not bad exercises.

They were just potentially more relevant to the area I was trying to calm down.

That distinction is important.

Good rehab is rarely about labelling exercises as good or bad. It is about choosing the right exercise for the right person, at the right time, in the right dosage.

An exercise that is too much in week one may be exactly what you need in week eight.

Different Exercises Load Different Parts of the Knee

One of the papers that helped guide my thinking was a study by Van Rossom and colleagues looking at knee joint loading during common rehab exercises.

The key takeaway was simple:

Different rehab exercises load different parts of the knee differently.

Some exercises increase patellofemoral load more. Some bias the medial or lateral compartment more. More knee flexion can also shift force further posteriorly on the femoral condyles.

That means rehab can be staged more intelligently.

Instead of saying, “I need to strengthen the quads”, I could be more specific:

• Can I train the quads without aggravating the lesion?

• Can I use a range that gives me a training effect without creating a flare-up?

• Can I build capacity first, then gradually reintroduce the more provocative positions?

• Can I monitor the knee’s response over the next 24 to 48 hours?

This was the difference between randomly adding exercises and actually designing a progression.

Kneecap Load Is Not Equal Across Activities

The other thing I had to consider was the amount of compression through the patellofemoral joint:

• Walking is relatively low-load.

• Stairs and squats sit higher.

• Running is higher again.

• Hopping can be one of the bigger loads.

Again, this does not make any of these activities bad.

It just means timing matters.

A runner might be able to walk comfortably but flare with stairs. They might tolerate a bike session but not downhill running. They might be able to do short-range strength work but not step-downs. They might be fine during the session, then wake up the next day with swelling or stiffness.

That does not mean rehab has failed.

It may simply mean the knee was not ready for that particular load, in that particular range, at that particular time.

Why Not Just Load By Pain?

This is a fair question.

Why not just let pain guide the whole process?

Pain is useful. I still used it. But with cartilage and bone injuries, pain is not always the whole story.

The response can be delayed.

Something can feel fine during the session, but later that day or the next morning the knee may feel swollen, stiff or restricted. For my knee, swelling and range of motion were often more useful indicators than pain alone.

So I watched:

• Swelling

• Range

• Stiffness

• Next-day response

• Where the exercise loaded the knee

The goal was not to ignore pain.

It was to make better decisions than pain alone could give me.

What My Early Rehab Looked Like

Early rehab was not about hammering the knee.

It was about calming the joint down, restoring confidence, and finding ways to keep loading without repeatedly poking the injured area.

The main goals were:

• Reduce swelling

• Restore range of motion

• Keep the quads active

• Maintain strength where possible

• Avoid heavy mid-range compression early

• Use cross-training that did not flare the knee

• Monitor the next-day response

This meant using more controlled options early, such as short-range quad loading, isometrics, hip-dominant strength work, bike or other cross-training, and carefully selected gym exercises.

It was not that I avoided knee loading.

I just tried to be more precise with it.

Progression Was About Earning Back Load

As the knee settled, the goal was to gradually earn back the movements I had initially respected.

Stairs.

Squats.

Lunges.

Hops.

Running.

But the progression had to be based on response.

Could I do the exercise without the pain increasing significantly?

Did swelling stay settled?

Was the range still good the next day?

Did the knee feel normal walking downstairs?

Could I repeat the session without accumulating irritation?

That was the real test.

Not just whether I could complete an exercise once.

The Biggest Lesson

The biggest lesson from this injury was that good rehab is not simply about avoiding load.

It is about using the right load, in the right range, at the right time.

Science did not give me a perfect recipe. It did not tell me exactly what to do every day. It did not replace clinical reasoning or listening to the knee.

But it did give me a better question:

What does this exercise actually load?

And for this injury, that question changed everything.

Key Takeaway

If you are rehabbing a knee injury, especially one involving cartilage or bone, pain is important, but it should not be the only thing you monitor.

Look at the bigger picture:

• Where does the exercise load the knee?

• How much does it load the knee?

• What range does it load?

• How does the knee respond later that day?

• How does it feel the next morning?

That is not overcomplicating rehab.

That is making it more specific.

References

• Cleather, D. J., et al. (2013). Hip and knee joint loading during vertical jumping and push jerking. Clinical Biomechanics, 28(1), 98–103.

• Escamilla, R. F., et al. (1998). Biomechanics of the knee during closed kinetic chain and open kinetic chain exercises. Medicine & Science in Sports & Exercise, 30(4), 556–569.

• Escamilla, R., et al. (2022). Patellofemoral joint loading during the performance of the forward and side lunge with step height variations. International Journal of Sports Physical Therapy, 17(2), 174–184.

• Goulette, D., et al. (2021). Patellofemoral joint loading during the forward and backward lunge. Physical Therapy in Sport, 47, 178–184.

• Hart, H. F., et al. (2022). May the force be with you: understanding how patellofemoral joint reaction force compares across different activities and physical interventions: a systematic review and meta-analysis. British Journal of Sports Medicine, 56(9), 521–530.

• Hofmann, C. L., et al. (2017). Trunk and shank position influences patellofemoral joint stress in the lead and trail limbs during the forward lunge exercise. Journal of Orthopaedic & Sports Physical Therapy, 47(1), 31–40.

• Powers, C. M., et al. (2014). Patellofemoral joint stress during weight-bearing and non-weight-bearing quadriceps exercises. Journal of Orthopaedic & Sports Physical Therapy, 44(5), 320–327.

• Ristow, A., et al. (2020). Patellofemoral joint loading during single-leg hopping exercises. Journal of Sport Rehabilitation, 29(8), 1131–1136.

• Seedhom, B. B. (2006). Conditioning of cartilage during normal activities is an important factor in the development of osteoarthritis. Rheumatology, 45, 146–149.

• Van Rossom, S., Smith, C. R., Thelen, D. G., Vanwanseele, B., Van Assche, D., & Jonkers, I. (2018). Knee joint loading in healthy adults during functional exercises: implications for rehabilitation guidelines. Journal of Orthopaedic & Sports Physical Therapy, 48(3), 162–173.

• Wallace, D. A., et al. (2002). Patellofemoral joint kinetics while squatting with and without an external load. Journal of Orthopaedic & Sports Physical Therapy, 32(4), 141–148.