All About Knees | A Running Digest

knee

Knees seem to be a problem area for many runners, so I’ve done my best to compile information about knee pain, its causes, and preventative measures.

I’ve included articles and journals as reference for the information given.

TL;DR

Loosen up your quads
Strengthen your hip abductors and glutes
Take stock of your gait and any possible faulty movement patterns

Knees, Knees, and More Knees

I’m beginning with what might be my favorite thing I’ve learned thus far as it’s easy to implement and something I now utilize before every run or lift session.

You should foam roll before your workouts in order to loosen up your quads, as it can prevent knee pain. This is because if your outer quad muscle is tight, it is unable to properly absorb force. Since the outer portion absorbs more force than any of the other quad muscles – that can spell trouble.

Tightness in that area will cause a significant amount of pressure to be transferred to the kneecap and patellar tendon, which can lead to the development of patellar tendinopathy (1).

I won’t get into impaired neuromotor coordination or “motor engrams” here as I feel that it is a separate topic deserving of its own space, but I’ll try to sum up some relevant bits:

Ankle sprains can cause decreased activation of the glutes resulting in stabilization issues with the knee and hip in which the knee can twist inward excessively.
Issues can also arise following even a minor knee injury. After healing there can still be stabilization issues with the inner quad muscle. Without proper stabilization, the patella can drift and cause chronic knee pain.
There is a study that references these motor engrams involving the ankle. There was some mention of the hip and knee in the abstract, but I unfortunately could not access the full article (2).

How We Run Also Affects Our Knees

Adjusting your cadence can also help with chronic knee pain. A study in 2019 had a group of runners increase their cadence by 10% with the aid of a metronome. The results were: less pelvic drop, less adduction of the thigh, and less knee flexion upon ground contact (3). The runners were re-evaluated three months later, and reported both a weekly mileage increase, and less knee pain.

Transitioning from a heel strike to a forefoot strike can reduce the load on the back of your knees by 50%. Alternatively, you can lean slightly farther forward at the hips during contact as this has been shown to redistribute pressure away from the knee, and into the hamstrings.

Now I don’t know if a combination of both forefoot strike and the leaning technique can even further reduce pain and pressure, but it could be worth giving it a shot if you’re having problems. I say this because there is research that shows the best runners in the world make initial contact with their upper body slightly tilted forward (4). The assumption here is that since they’re mid to forefoot strikers, this could bode well for knee pain.

Excessive pelvic drop, which can be diagnosed by a gait test – can cause IT band, anterior knee, and lateral hip pain (5). This can be corrected by perfoming isometric hip excercises; however, some runners’ bodies compensate for weak glutes by causing the adductor magnus to fire during ground contact. So although weak hip abductors were originally blamed for pelvic drop, newer research suggests that it could be due to a weak gluteus maximus (6). This creates a pelvic drop that does not respond to the conventional exercises.

I’m wondering if this can be further counteracted by strengthening both the hip abductors and adductors, but if you’re already doing squats and glute bridges, then maybe just stick to that. Unless of course you want to put the time and effort into adductor strengthening, but this is just conjecture.

Excessive pronation can cause not only anterior knee pain, but also achilles injuries, and medial tibial stress. Runners with high arches are more likely to develop stress fractures, lateral knee pain, and outer hip pain.

Overpronators should look to perform foot strengthening exercises and or wear minimalist footwear. High-arched runners should consider gait retraining that focuses on reducing impact during contact, and striking the ground with the tibia nearly vertical in order to reduce braking forces (7).

Speaking of arches – it has been frequently cited that low arches specifically are the cause of retropatellar pain, but a 2001 study showed that runners with high and low arches have the same potential for patellofemoral pain (8).

Lastly, strengthening exercises alone will not correct faulty movement patterns, so you should still work on modifying any issue with your running form as a strong muscle can still fire inappropriately. This was demonstrated in a study of runners who suffered from inward collapse of their knees (9). Although strength increased by about 50%, there was no change in running style, and their knees continued to collapse inward.

Hips Are Also Important

A study of basketball and track athletes found that low strength in the hip rotators and abductors can cause the knee to be prone to injury as they control rotation (10).

Using a similar protocol, another study was done for athletes in various sports. Those who were unable to generate 20% of their body weight with a seated hip rotator test were seven times more likely to tear their ACL (11).

Hip abductor strength also has an added benefit of preventing fractures of the femoral neck, which connects the femoral shaft with the femoral head.

A 2003 study showed that patellofemoral problems were caused by exaggerated rotation of the femur which led to the outer aspect of the femur shifting into the patella, and was supported by follow up studies in 2008 and 2010 (12, 13, 14). Hip weakness was cited as the cause of this rotation, and another study was done to prove that weak hip abductors are what allow the femur to turn in excessively (15). This rotation increases when runners are fatigued.

The American College of Rheumatology was able to determine that people with strong hip abductors are less likely to develop osteoarthritis in the knee, as I had briefly mentioned earlier. This is because the abductors not only prevent inward rotation of the thighs, they also create a force on the outside of the knee that prevents it from collapsing inward (16).

The study was done on folks with bowed legs, and showed a reduced progression of arthritis in those with strong hips. This was regardless of age, sex, and the degree to which their legs bowed – which demonstrates that strength can protect you from injury even if you are poorly aligned. This also applies to knock-kneed runners.

What Else Can Be Done

Orthotics can help with patellofemoral pain, and can be tested by performing some single-leg squats (17). This has the potential to reduce knee pain increases by 25%-45%. Performing foot exercises while utilizing orthotics has shown to be more likely to produce good results (18).

Also consider quadricep flexibility, as mentioned at the beginning of this page. This is further backed up by these studies done in Belgium (19) and Hong Kong (1). Foam rolling or a massage stick, along with a standing quad stretch repeated throughout the day should help. Make sure to massage the entire muscle, not just the lower portion.

If returning from retropatellar injury, consider a neoprene knee braces or kinesiotape of the top of the patella. You can also try a triple stick strap, which is a compressive brace that helps stabilize the kneecap during recovery.

For patellar tendinopathy, outside of the foam rolling – a compressive strap can reduce strain by distributing forces over a broader area (20, 21).

According to studies, the most effective way to treat patellar tendinopathy is to increase the strength of the patellar tendon with heavy weight training (22). Researchers from Denmark had individuals complete a 12-week protocol which included squats, leg presses, and hack squats. That being said, please use caution if you’re just getting into strength training, and maybe moreso if you’re rehabbing or coming back from an injury. A long-step forward lunge with dumbbells is a good one to use if you’re not keen on hitting the gym quite yet, or at all.

And that’s really it all I’ve got. This actually ended up being much longer than I’d originally planned as I continued to discover new information while jotting everything down. If you made it this far thank you, but mostly I hope that this was useful to you or at the very least, somewhat informative. If I come across any new information, I’ll be sure to add to this or create another post that references this one.