The series of ACL (anterior cruciate ligament) injuries to prominent NBA stars has been a major storyline in the league over the past few months.
Stars Al Jefferson (2009), Kendrick Perkins (2010) and David West (2011) injured their knees in the not-too-distant past.
Then the floodgates opened in the spring of 2012, with the likes of Ricky Rubio, Iman Shumpert and Derrick Rose tearing their ACLs. The 2012-13 season hasn't been any kinder, with Brandon Rush, Rajon Rondo and Lou Williams biting the dust.
Is there a logical explanation for this rash of ACL injuries in recent years?
We looked at trends in the sport today and also spoke with licensed family physician Dr. John O'Brien, M.D., who has more than 25 years of experience dealing with sports-related knee injuries.
Professional athletes have become substantially stronger and more explosive over the past couple decades, with increased muscle mass and heavier frames.
Unfortunately for their knees, the joints haven't kept pace.
The ACL is one of the four ligaments in the knee that connect the knee joint to the shinbone, and it collaborates with the PCL (posterior cruciate ligament) to control the knee's rotation.
Modern NBA players are able to pack on muscle like never before, but joints and ligaments haven't evolved as much over the years.
"The joints haven't changed much in the last 20 years or so," said Dr. John O'Brien, "but the physiques and muscle structures have."
The impact and force caused by the mass of today's athletes contributes to greater risk for knee joint injuries.
When these ultra-muscular players go flying in the air, the likelihood for ligament damage escalates.
The acrobatic nature of today's NBA creates a pounding on the joints that wears them down and can often lead to injury.
Ballers are unbelievably explosive these days, and they're reaching new vertical limits. Thus, sticking the landing is getting trickier.
"A lot of it has to do with hangtime," said Dr. John O'Brien. "Any time you're in the air, it's an unpredictable situation. When you come down, there's often an uncontrolled impact."
We're not talking about jumping jacks in gym class. These are world-class athletes leaping at a frenetic pace and getting pushed and knocked off-balance in mid-air. They're jumping, running and changing directions faster and harder.
Odds are that there will be a few ACL casualties along the way.
No matter how much treatment, technology and nutrition NBA players get, the human knee joints can only take so much poundage and mileage throughout a season and a lifetime.
The extensive training and competition schedule of the Association doesn't spare those knees any miles.
Offseason training is more involved, the preseason is a month long and the postseason is longer since it was expanded in 2003.
Many players log 200-plus minutes in the preseason, 2,000-plus minutes in the regular season and anywhere between 500 and 1,000 minutes in the playoffs. That means some spend well over 3,000 minutes per season in the heat of battle. And that's just game time.
On top of those thousands of minutes of high-intensity competition are all the minutes spent in training, practicing and scrimmaging.
The bottom line is that NBA stars are registering more miles per year than they were years ago.
In addition to the massive workload at the pro level, NBA players are entering their 20s with more mileage than they used to.
Over the past decade, middle school and high school prospects have seen an uptick in competition, exhibitions camps and All-Star events. They play for their school teams, then AAU teams, along with multiple All-Star showcases and skills camps.
It's rare that a young hoops star does anything but basketball all year round. Gone are the days of playing a low-stress sport like baseball in the spring and taking significant time off in the summer.
"Kids are being pushed to excel at a younger age," said Dr. John O'Brien. "It tends to improve certain muscle groups, but not all. You see them overusing certain joints, especially at the high school and college level."
That helps explain the increased frequency of stars tearing their ACLs early in their careers, like Derrick Rose and Iman Shumpert.
The increased muscle mass and explosiveness of NBA athletes combined with the rigors of the year-round schedule puts the knee at a greater risk.
When the shin bone and the thigh bone move in opposite directions with such rapid and powerful force, the ACL is put to a grueling test.
Almost everything about the NBA has become bigger, faster and stronger—except for knee joints. The joints have grown over the years, but not big enough or proportionally enough to support the thighs and upper bodies of professional athletes on intense impact.
Until designers and scientists can create truly effective (yet unrestrictive) preventative apparel, the ACL injuries won't subside.
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