If you play basketball seriously, you probably jump more than you realise.
Every practice includes jump shots, rebounds, layups, defensive slides, and sprints. Each one of those movements sends force through your knees and over time, those forces add up.
Most players think about ankle sprains or ACL tears when they think about basketball injuries. But one of the most common injuries in jumping sports actually develops much more quietly. It starts as a small ache below your kneecap. Maybe it appears after a long training session or a game. Maybe it disappears after a day or two but it always comes back again. This injury is called patellar tendinopathy, often referred to as jumper’s knee. And if you play basketball regularly, your body is constantly managing the forces that can lead to it.
Understanding why this injury happens is the first step to preventing it.
Inside your knee is a thick band of connective tissue called the patellar tendon. Its job is simple but incredibly important. It connects your quadriceps muscles in the thigh to your shin bone and allows your knee to straighten. Without it, jumping would be impossible.
Every time you explode upward for a rebound or push off for a sprint, your quadriceps contract and pull through the patellar tendon. That force travels through the tendon into the lower leg, allowing your body to move.
But here is the important part. When you land, that same tendon has to absorb the force of your body hitting the floor, and those forces are not small. Landing from a jump can place multiple times your body weight through the knee joint. For basketball players who may jump hundreds of times each week, the patellar tendon is constantly under stress.
Most of the time, this is not a problem. The body is remarkably good at adapting to stress. But when the load placed on a tendon becomes greater than its ability to recover, problems begin to develop.
For many years, people believed tendinitis was simply an inflammatory injury. The idea was that the tendon became irritated and inflamed after too much activity but research over the past two decades has shown something more complex. In many cases, jumper’s knee is not primarily about inflammation. Instead, it involves structural changes within the tendon itself.
Tendons are built mostly from type I collagen fibres, which are arranged in highly organised parallel bundles. This structure allows them to transmit large forces while remaining strong and flexible. When a tendon experiences repeated overload, small microscopic injuries can occur within this structure. If recovery time is insufficient, the tendon cannot fully repair the damaged fibres.
Over time, several changes may occur inside the tendon:
This process is often described as a failed healing response, where the tendon attempts to repair itself but never quite returns to its original structure (Canosa-Carro et al., 2022; Theodorou et al., 2023).
Another interesting change that can occur is neovascularisation, where new blood vessels and nerve fibres grow into the tendon. These new nerve fibres are thought to contribute to the pain athletes feel during jumping or sprinting. So while the outside of the knee might look completely normal, the internal structure of the tendon may already be changing.
Not all sports place the same stress on the patellar tendon. Sports that involve frequent jumping create the highest loads. That is why jumper’s knee is most common in basketball, volleyball, and track and field jumping events.
Epidemiological research shows that approximately 14–20% of elite athletes develop patellar tendinopathy. In sports that involve high volumes of jumping, the prevalence can reach 30–45% of athletes (Theodorou et al., 2023; Llombart et al., 2024). Think about what happens during a typical basketball practice. Players repeatedly perform explosive movements:
Each of these movements places stress on the patellar tendon. When those stresses occur again and again over weeks and months, the tendon can gradually become overloaded.
One of the reasons jumper’s knee becomes a long-term problem is that it usually starts small. Most athletes first notice something subtle. It might feel like:
At first, the pain may disappear after warming up. Many players assume it is just normal soreness but over time, if the tendon continues to be overloaded, the symptoms can gradually worsen. Pain may begin to appear during activity, not just after it. Eventually, jumping performance can start to decline.
Recognising these early warning signs is extremely important.
Two players can train in the same gym, run the same drills, and jump the same number of times, yet only one develops jumper’s knee.
Why?
The answer usually comes down to capacity and load. Every player has a different capacity for their tendons, with some players being more vulnerable to the aforementioned internal tendon damage. Hence, it is important to understand your tendon’s limits for mechanical stress. If the load placed on the tendon stays within its capacity, the tendon adapts and becomes stronger. But if the load exceeds that capacity, damage accumulates.
Several factors can increase the risk of overload:
These factors reduce the tendon’s ability to handle stress (Theodorou et al., 2023; Llombart et al., 2024).
The encouraging part of this story is that tendons are highly adaptable tissues. When they are loaded progressively and given enough time to recover, they become stronger and more resilient. This is why many prevention programmes focus on building tendon capacity, in addition to avoiding stress.
Several strategies have been shown to help reduce the risk of jumper’s knee.
Strength training improves the ability of the muscles and joints to absorb force. Eccentric exercises, which involve controlling the lowering phase of a movement, stimulate tendon remodelling.
Learning proper landing mechanics can also make a significant difference. When athletes land with their knees and hips flexed, the forces of impact are distributed more evenly across the body.
Perhaps most importantly, training loads should increase gradually. Tendons need time to adapt to new stresses.
These strategies help ensure that the load placed on the tendon stays within its capacity (Canosa-Carro et al., 2022; Llombart et al., 2024).
For players between the ages of 15 and 18, training volumes often increase rapidly. Athletes may play school basketball, club basketball, and additional training sessions each week. This is exactly the stage where overuse injuries can begin to appear. Understanding tendon health at this stage is important because habits formed now can influence long-term performance. Preventing jumper’s knee is not just about avoiding pain. It is about building a body that can handle the demands of high-level basketball. Basketball places incredible demands on the body, especially on the knees. The patellar tendon absorbs huge forces every time a player jumps or lands. When those forces accumulate faster than the tendon can recover, patellar tendinopathy can develop.
But the story does not end there. With the right approach to strength training, landing mechanics, and load management, tendons can become stronger and more resilient. For basketball players who want to keep jumping higher, moving faster, and staying on the court longer, understanding tendon health is one of the most valuable investments they can make.
Canosa-Carro, L., Bravo-Aguilar, M., Abuín-Porras, V., Almazán-Polo, J., García-Pérez-de-Sevilla, G., Rodríguez-Costa, I., López-López, D., Navarro-Flores, E., & Romero-Morales, C. (2022). Current understanding of the diagnosis and management of tendinopathy: An update from the lab to clinical practice. Disease-a-Month.
Llombart, R., Mariscal, G., Barrios, C., & Llombart-Ais, R. (2024). The best current research on patellar tendinopathy: A review of published meta-analyses. Sports.
Theodorou, A., Komnos, G., & Hantes, M. (2023). Patellar tendinopathy: An overview of prevalence, risk factors, screening, diagnosis, treatment and prevention. Archives of Orthopaedic and Trauma Surgery.