PFP is our CTE

Football players are plagued by the disease chronic traumatic encephalopathy (CTE). It’s a neurodegenerative disease that results in mood swings, behavioral changes, and dementia — and can only be definitively diagnosed post mortem. CTE patients were tied together by a common history of repeated blows to the head, and in a 2017 survey of autopsies, 87% of former football players had CTE, including 110 out of 111 National Football League players. Even sadder is that the sample included high school and college players – and the latter had a rate of 91%. This should be damning evidence that regardless of the helmets used, it doesn’t dissipate the causative agent of CTE.

CTE is a type of injury that accumulates slowly over practice, and is difficult to diagnose and get counted over short survey periods. Acute injuries are more readily measured and get the attention – broken bones, sprained joints, bruises – but chronic injuries like this may only be evident after it’s too late to deal with them.

Patellofemoral pain (PFP) – colloquially referred to as jumper’s knee – is the CTE of volleyball. PFP is so prevalent among current and former volleyball players that it’s usually considered a standard developmental feature. Coaches tend to lump it into the category of general overuse injuries, but the consequences of PFP are lifelong and debilitating.


Pathogenesis of patellofemoral pain from Petersen et al, 2017.

The sad truth is that PFP, once it is present, is multifactorial and doesn’t have a single ready cure. There’s the chronic pain itself, which can wear down the quality of life  of the patient, and the instability is a potential lead to more drastic injuries like ACL tears or worse. Conservative exercises are generally used to relieve the pain, but it doesn’t remove the damage – and the terminology . Most any other interventions pretty much take the player out of the game. The best cure is not to get hurt in the first place. And, like CTE, we have data pinpointing that total jump volume and intensity are the risk factors for PFP; more accurately, it’s the nature of landing.

Every jump has a price.

Volleyball culture has built a premium on the jump as a way of accomplishing a vertical enhancement, but hasn’t considered the consequences of those jumps. The higher the jump, the greater the energy the player has to absorb and dissipate on impact – the force of impact can be ameliorated by extending the landing time. People can fall from great heights and survive if they are traveling with an angle along the ground; rolling extends the time of impact.

To accomplish maximum vertical extension, volleyball players are taught to jump straight up – which means they land pretty much with near instantaneous impact time, and maximum force. Moreover, current net play strategies provide no room for horizontal travel when landing. The accumulated volume of this practice figures into the etiology of PFP – no amount of padding or taping or bracing changes the physics. If anything, due to the cumulative nature of damage, these practices may aggravate the situation through the creation of moral hazards.

The quandary is one for coaches – are we willing to change the very strategies of the game? The exercises that “strengthen” the knee don’t address the physics and angles that happen in current game play, and I haven’t encountered studies that can rule them as preventative. In fact, that’s the issue with PFP – it’s a disease with lifelong consequences that we may not see while athletes are younger, and controlled interventions will take years or decades to determine effectiveness. Like football, it involves addressing the very culture of the sport. Should coaches treasure the longevity of the athlete enough or do we gamble their health since it’s a consequences they won’t have to pay?


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