Why Overuse Causes Tendon Injuries and What to Do About It

STACK Expert David Taylor offers a primer on tendons—their physiology, the dangers of overuse and how to prevent it.

One of the hot topics in sports medicine at the moment is tendon injuries. Explosive sports, especially basketball, involve excessive tendon recruitment, which can lead to problems in the kneecap area or jumper's knee. These injuries have a history of being misunderstood, causing problems to recur over and over again.

An NBA review of injuries noted that front-knee inflammation accounted for the greatest number of practices and games missed. Interestingly, time loss is probably a poor measure of a tendon injury, because so many athletes play through pain, albeit with reduced function. A good example is Cleveland Cavaliers guard Kyrie Irving. In last year's NBA Playoffs, he was hampered by "knee tendonitis," but despite increased stress on his knee joint, he kept playing and ultimately fractured his patella.

RELATED: Achilles Tendon Ruptures: Prevention and Recovery

What Are Tendons?

Tendons are connective tissue that link muscle to bone. Healthy tendons are densely packed collagen fibers, uniform in nature. When you work a muscle, you also load its associated tendons, causing them to get strong along with the muscle. Everybody is familiar with Delayed Onset Muscle Soreness (DOMS), the feeling caused by microtears in the muscles. But there is no tendon equivalent of DOMS; we don't feel tendon damage; and muscles repair themselves faster than tendons. Unfortunately, younger athletes especially (but also older ones) load these structures without knowing what recovery is required. This leads to slow degeneration of the structures and a reduction in their ability to withstand load.

Figure 1 below is a simplified summary of the tendon pathology continuum—normal, reactive, disrepair and degenerative. A large percentage of tendon ruptures (especially the Achilles) occur without prior onset of pain.

RELATED: Pectoral Tendon Ruptures and Injury Prevention

We use the analog of Swiss cheese or a frayed rope to indicate a degenerated tendon and its reduced ability to withstand load. To visualize a fresh healthy tendon, think of a brand new rope and two people pulling it in opposite directions. Repeated bouts of activity, such as high load bounding, place stress on the tendon, slowly cutting away and fraying the middle of the rope. Two people then pulling the rope from opposite ends results in the rope snapping.

Tendon Pathology Continuum

How Can We Tell When a Tendon Is Overused?

Tendon pain is an interesting topic. Athletes feel pain when a tendon becomes "reactive" due to its inability to tolerate the demands of the loads placed on it. Pain symptoms remain localized—generally, you can point to the pain site with one finger.

Evidence suggests that anti-inflammatory treatment is useless, since no inflammation occurs within a tendon. Rest alleviates the pain over time, but it does not address or improve the tendon's capacity to tolerate more or higher demands. This increases the liklihood of further injury. Rest is like fake rehab because it doesn't address the root problem. When an athlete stresses the tendon with demands it could not previously tolerate, the pain will return. It might even occur at a lower threshold, because between painful events, further degeneration has taken place. Over time, the capacity of the tendon reduces.

RELATED: Anatomy, Treatment and Rehab for a Biceps Tendon Injury

What's Dangerous for a Tendon?

So what can tendons tolerate? This is an area of continuing research. We know that jumping places a high demand on the patella tendon, and the higher you jump, the greater the stress. Similarly, sprinting on your toes or up a hill places a heavy load on the Achilles tendon. A rapid increase in the weight load of a muscle-building training program—e.g., going from lazing around on your couch to suddenly performing an intense workout—or playing increased minutes during a game are additional risk factors.

How Can We Prevent Tendon Injuries From Happening?

Ideally, athletes have access to a sports performance professional who works to reduce the risk factors. Wearable technology makes this a lot easier, because it allows us to track workloads and notice drastic changes from the norm. After a particular high-load workout or intense game, the body might need 48 hours to recover. And that's OK. It needs it.

But the biggest takeaway should be this: the body likes consistency. Have you ever wondered why, after an long break over the holidays, you develop all sorts of aches and pains when you get back into activity? It's because your muscles and tendons have deconditioned, then you suddenly subject them to stress that's simply too high. Sufficient pre-season and consistent loading is what the body loves, which is why NBA players work year-round, even when they're not playing.

It is exceptionally difficult to curtail symptoms during the season, with its repeated demands of spring-loaded activity required to participate in sports like basketball. That's why it's important to monitor distance traveled and limit high-impact jumping, if possible. For example, it's not advisable to do plyometric workouts during the season. Practices and games subject your tendons to plenty of stress. You don't need to add more.

RELATED: What it Takes to Recover From an Achilles Injury

I hope this helps you understand why you might recurrently develop pain during certain times of the season, and from season to season why it won't go away. Getting on to it early can aid in your rehab. Some of you may have tendon issues without even knowing it. As your tendons get further along the continuum, they are harder to manage, because degenerative tissue is difficult to restore.

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