So why is terminal knee extension so important?
1. If your joint does not have full range of motion in all directions, it is not normal/healthy. Now, an athlete can manage this restriction in terminal knee extension for some time, until they can’t and they come to me with pain – in the knee or elsewhere. Without this critical range of motion they are predisposing the joint to high loads at a mechanical disadvantage.
2. If your knee is unable to get straight and then we stack some loading on top of it, think deadlift or jumping/landing, the joint is unable to fully disperse this load across the joint surface. A fully extended knee is considered the close-packed position of the knee because it is the position in which the articular surfaces are most congruent and the ligaments are the most taut. If you cannot obtain full extension, the load is poorly dispersed and cartilage does not do well with repetitive loading to a localized area. Here is some great evidence on the correlation of knee motion and early arthritic changes. Don’t wear a hole in your knee!
3. In addition to the cartilage loading, lack of terminal knee extension means that you are unable to lock out the knee and the angle of pull on the patella and patellar tendon is altered, causing increased compression of the patella against the knee. This may lead to Patellofemoral Pain Syndrome and possibly patellar tendinitis due to the increased off-axis pull on the patella.
4. Perhaps most importantly, you need full knee extension to generate optimal quad force production. We will typically see poor quad function toward knee extension in those who are restricted in this motion. I don’t need to tell you how important force development is for your quads. Any loss in quad function can destabilize the knee and increase joint loading.
Here’s the kicker, loss of terminal knee extension will likely cause deficits up and down the kinetic chain. If you’re unable to get your knee straight during triple extension (ankle plantarflexion, knee and hip extension) which is needed in basically all athletics, the hip cannot get into neutral extension causing you to overextend at the lumbar spine in order to keep you upright. Blow through some reps like that with hip flexors that are now super tight and it’s hello spondy, plus it just looks like weak sauce. You may also have difficulty with appropriate foot strike during running, but that’s a whole other topic.
– Seth
Nice article.
I have this problem for years, i can’t full extent my knees. I suffer from chronic back pain (muscle spasms) and can’t stand up for even 10 minutes. Also i have anterior pelvic tilt and my hamstring isn’t tight at all. What should i do now? 🙁
Go see a physio/physical therapists. Do some research on the physio first. Not all physios are created equal when it comes to their knowledge and practice.
Thanks for the article Seth.
Do you ever run into athletes with lack of terminal knee extension, but also some swelling in the knee? Wondering how this would effect the correction of things.
Hi Luke,
Sorry for the late reply. Yes knee joint effusion (swelling) directly affects the ability to fully straighten the knee. The swelling takes up physical space in the knee and prevents it from mechanically straightening. It also inhibits muscular contraction around the knee joint, thus making it more difficulty to actively straighten it. Great questions!
Did Jared(in the video) restored his knee extension?
Hi Glen, yes he did!
As a home care therapist for over 25 years I have taken the initiative to build a home care program that focuses on the incremental approach to achieving terminal extension of the knee and hip. My approach is achieved by introducing a 2 inch block system that limits the strain to soft tissue musculature surrounding the surgical site..
I would welcome the opportunity to share this approach with other fellow therapist
Hi Rich, please do!
Hi Seth, do you have a separate post that discusses screw-home rotational component for full extension? Is this similar to Kelly Starretts distraction and tibial rotation whilst firing quad technique?
2 years after TKR on both knees I started losing extension in both knees. I was at 0 degrees in my left knee and -3 degrees after completion of therapy post surgery. Now I am at -17 degrees in my left knee and -15 degrees in the right. My Physician is at a loss as to why as I work at a gym and exercise 5 days a week using some of the exercises I used in therapy. I am having moderate pain in the left knee and have a visible limp as I walk. I hate my knee replacements. I am 66 years old and maintained an athletic life style until I had the replacements at 60 years of age. I have a history of Osteoarthritis.
I sprained my right knee at the end of April and limped around in moderate pain for almost two weeks, then decided to go see a dr. Long story short, bad insurance, took two more weeks to see orthopedic dr Who then diagnosed me with a bucket tear meniscus he said that my language now locked at a 60° deficit. It took over two weeks to get MRI and when I went back to see orthopedic doctor I did not have a torn meniscus. But I had spent two more weeks elevating my leg in a bent position on a pillow because it felt more comfortable and less painful in that position. Now a few months later I have a 60° bend in my right leg and have started physical therapy and splinting. After four weeks of four times a week going to physical therapy and splinting for 3 to 6 hours a day I’m down to 25°. Doctor and physical Therapist don’t understand why I have such a severe contracture when I just started with the knee sprain. The physical therapy is painful and the splinting is painful and I’m at my wits end. Has anyone out there ever heard of someone getting such a severe contracture after 5 to 6 weeks of having a bent leg today with Brighto therapist don’t understand why I have such a severe contracture when I just started with the knee sprain. The physical therapy is painful and the splinting is painful and I’m at my wits end. Has anyone out there ever heard of someone getting such a severe contracture after 5 to 6 weeks of having a bent leg for 5-6 weeks. Please help!!