Podcast #116: Patellofemoral Pain and Bone Stress Injuries with Rich Willy


Patellofemoral Pain (PFP)

“I try not to use the term treatment when it comes to, I probably prefer the term management.”

“If you go out and you make a training load error, that training load error is going to manifest itself as that past injury that you had and that’s probably because you still have those underlying risk factors.”

“PFP is kind of just there and it also gets worse as you go on [whereas it gets better with patellar tendinopathy].”

“I like calling patellofemoral pain the low back pain of the lower extremity because we don’t really know what’s causing this, what is the pain generator.”

Hyperextended knees: “Inferior pole of the patella can pinch the fat pad.”

“Static Q-angle does not predict who is going to develop patellofemoral pain.”

What is causing the pain in PFP? “No one really knows.”

“The number one predictor on how quickly you’re going to recover from PFP is how long you’ve had it.”

Not a grown pain: “High schoolers who have PFP turn into young adults who have PFP.”

“Patellar tracking, patellar alignment, all these things we used to think that related to PFP, don’t seem to relate to PFP for real.”

“For me, I use a lot of patellar taping… I just give them a nice medial pull.”

“It doesn’t seem to be that taping is changing this person’s PF joint alignment, it’s probably just that really noxious stimulus of this tape just pulling the heck out of this person’s skin when they’re doing some sort of activity… distracting the central nervous system.”

PFP: “People will have hip weakness.”

“Hip weakness doesn’t necessarily cause PFP, it’s the other way around. The PFP is causing hip weakness.”

Irritable PF joint: “spend some time doing some proximal loading, plantarflexor loading, then we’ll start sneaking in some quadriceps strengthening (step ups, forward lunges) before we get them on some heavy loading program for their quadriceps (heavy squats, knee extension machine)…

“I think if you go after that [PF loading] right from the get-go for people who have PFP, they’re probably not going to do very well. Versus someone who has PT, that what you would start doing to do on day one. On day one, you’re going to start doing heavy knee extensions. Everyday that you delay doing that with someone who has PT is one more day that they’re going to have PT. But if you do that with someone who has really irritable PFP, they’re going to get really flared up and you’re going to take a couple steps back.”

“I don’t think we have to be as specific as we used to think when it comes to PFP. With patellar tendinopathy, you have to be very specific.”

“If you know what you’re doing, you should be able to come up with 2-3 exercises that are gonna get it done for them.”

“If you just run with a 3-5% incline on a treadmill, you’re going to reduce patellofemoral joint loads by 25%… of course, you’re splitting that between your hip and your plantar flexors… that’s one of the most efficient ways to keep someone running.”

“If you increase your running cadence by 5-10%, we know patellofemoral joint loads with decline about 10-15%, but you don’t have to do that when you’re running uphill, because you do that anyway.”

“Forefoot strike really reduces your patellofemoral joint loads but that’s going to dramatically increase your Achilles tendon forces as well.”

“Patellofemoral joint loads go down if you run in a minimalist shoe but of course Achilles tendon forces are going to go up.”

“Running with a forefoot strike does not reduce your risk of a running-related injury. You’re just choosing to get a different injury. You’re gonna get a foot and ankle injury instead of a knee injury… it does not improve your running economy, and it doesn’t magically make you a faster runner.”

“When you run and when you walk, your quadriceps actually do not contribute a lot to forward momentum… our quadriceps are predominantly being used to slow down our center of mass as we’re moving forward… that’s why when you go downhill or downstairs can be really provocative for someone with PFP.”

“If you take a really long stride and you have a heavy load on your back, your braking forces are gonna go up and those loads are gonna be absorbed through your patellofemoral joint.”

PFP: “It’s basically a training load error.”

“Sport specialization almost doubles your risk of developing patellofemoral pain.”

Post-ACL reconstruction: “30-40% strength deficits in their quadriceps but their hip extensors and abductors are stronger than their age-matched and activity-matched peers.”

Bone Stress Injuries

Two groups of bone stress injuries: “Athletes who are really under-fueling (e.g., runners)… athletes who are under a lot of Biomechanical loads (e.g., basketball players).”

Polar opposites: “athlete who is under-fueling whose physiology is unable to adapt… then an athlete who is fueling well but that is undergoing huge biomechanical loads.”

“Bone is highly vascularized… any time you see blood vessels, you know there’s a lot of metabolic activity going on there.”

“Trabecular bone is highly energy intensive… it requires a lot of energy to exist.”

“Bone cares a lot about where your calories are coming from.”

“Bone is very carb dependent.”

Low energy/fasting: “It accelerates bone breakdown and decelerates the amount of replacement.”

“There’s no more complex injury that I treat than a bone stress injury (sports RD, physician, the coach, the athlete, family in younger athletes).”

“Bone is highly estrogen/progesterone/testosterone sensitive… all three of those hormones reduce when we’re under-fueling.”

“The closer you get to the ground, the more biomechanics matter. The further you get away from the ground (more proximal), the more you need to be thinking about systemic issues.”

“When someone has a 5th or 2nd metatarsal bone stress injury, I’m always gonna be thinking more about biomechanics.”

“We used to think that loads on bones had to do with impact forces… that’s not actually the case at all.”

Running: “6-7x Achilles tendon bodyweight force… tibial bone forces 9-10 bodyweights… vertical GRF is 2-2.5x bodyweights… muscle is far and away the biggest contributor to bone forces.”

“The more collagen in a structure, the quicker it will be desensitized to load (e.g., bone and tendon).”

“Bone starts to lose its sensitivity to loading after about 60-90 loading cycles.”

“We always do the most intense activity at the very beginning of the session.”

“Bone responds to very very high loads that are applied very very quickly in very very short bouts.”

“Plyometrics don’t require a lot of energy, strength training does require a lot of energy.”

“You’re tapping into the passive energy storage and release capacity of your tendons. It doesn’t take a lot of energy to do plyometrics but you can get a really nice load on the bone.”

“To get a lot of load on the foot and ankle, you need to have very short contact times… to get a lot of loads on the femur, you wanna have longer contact times, I tend to cue them softer… you need to do a lot of single leg landing/side to side/hops to bend and twist the femoral neck.”

“Bone is most sensitive to high strain rate (speed that you’re trying to stretch)… Tendon is most sensitive to higher strain values (change in resting length).”

“Bone doesn’t respond well to heavy slow resistance training. It responds the best to heavy fast resistance training and that’s where the plyometrics come in.”

“The more sessions you do in a week, the greater the bone adaptation is going to be… you wanna have low volume, high intensity sessions but you wanna do them fairly frequently.”

Swimming and cycling: “They’re doing nothing for bone… you’re certainly not doing a bone building activity.”

“If you wanna see poor bone health, look at elite level cyclists in their 20s. They typically have the bone health of a 65 year old (non-weight bearing sport, training for really long hours).”

“PFP people are really gonna diminish the amount of activity that they do… people with bone stress injuries don’t do that… they will stay as active, they will get that caloric burn one way or another… if they continue to keep themselves in a state of low energy availability, their physiology won’t support their healing.”

“As muscle goes, bone will go.”

“If your muscles are having a hard time keeping up with the load you’re throwing on them, you can count on the fact that the bones are having a hard time as well.”

Week 4 or week 6 is when bone injuries show up: “If they get a bone stress injury in the first couples weeks of a new exercise program, you can feel confident that they actually got that bone stress injury before they showed up.”

“The only thing that really matters is how many times you’re jumping and cutting in a game. That is far and away the most damaging to the bone. Running and jogging up and down the court isn’t not gonna cause a lot of damage to the bone for the athlete.”

“The athletes that tend to have the greatest risk for bone stress injuries when it comes to basketball are gonna be your most explosive athletes (greatest muscle forces, best jumpers, longer legs, skinnier legs, metatarsals tend to be longer and skinnier.”

“If you’re in your 20s and if you could throw a 90 mph fastball and you decide (and you could) to throw it with your opposite arm, the humerus strength on your opposite side is about half that of your throwing side … you’ll pretty much break your humerus right away.”

“If you’re a soccer player in adolescence, it really reduces your risk of fracture in your 40s and 50s.”

Sever’s Heel and a heel lift: “that shifts his plantar flexors into more of an actively insufficient position so he can’t generate as much force from his plantar flexors… on a day when he’s really sore, he puts those heel lifts in and he typically can do okay.”

“The thing that really dramatically increases your risk of all these apophysitis is sport specialization.”

Top 3 for PFP treatment:

  • start proximal and then go more and more focal loading on the patellofemoral joint
  • use your adjuncts well… the whole point of those adjuncts is to get more load on this person
  • keep the activity levels as high as possible (e.g., cycling, uphill treadmill running for a runner)

Top 3 for bone stress injuries:

  • No pain is allowed. Unlike tendons and PFP, it’s not the case with bone. Pain after a loading session, take 3 days off and do non-osteogenic cross-training and then go back one step in your progression and just pick up where you left off
  • Don’t think about impact any more. Always think muscle
  • Control bone forces, think about controlling muscle forces. with plyometrics, you’re always going to get the most muscle forces.

Montana Running Lab Website: https://montanarunninglab.com

Rich Willy Twitter: https://twitter.com/rwilly2003

Rich Willy Instagram: https://www.instagram.com/montanarunninglab/