When Taylor Fritz walked onto Centre Court for his Wimbledon quarterfinal against Alexander Zverev, there was little reason to expect the American's tournament would unravel so quickly.
Fritz entered the matchup having won seven consecutive matches against Zverev, including a recent victory on grass in Halle. But instead of another tightly contested battle, the American fell in straight sets, 6-4, 6-4, 6-2, after what he later described as a sudden flare-up of right knee tendinitis that surfaced just a few games into the match.
"I don't really know what to say. I feel like three games into the match I just started feeling my knee," Fritz told reporters during the post-match conference, adding that while the injury affected him, Zverev's aggressive play would have made the match difficult regardless.
Fritz said the sudden onset left him shocked because he had felt healthy leading into the match.
The tennis player mentioned the only warning sign he had was a mild pain near the end of his fourth-round win over Alexander Bublik, but assumed it was only temporary.
Why Knee Tendinitis Can Flare Up Suddenly
Knee tendinitis, commonly called patellar tendinitis or "jumper's knee" when it involves the patellar tendon, is an overuse injury caused by repetitive stress rather than a single traumatic event.
The condition develops when repeated loading creates microscopic damage in the tendon faster than the body can repair it.
Symptoms often include pain below the kneecap, stiffness and tenderness that typically worsen during jumping, running or sudden changes in direction.
Although athletes may feel fully recovered after weeks or months of rehabilitation, tendons heal more slowly than muscles because they receive relatively limited blood flow.
Underlying tendon changes can persist even after pain subsides, leaving athletes vulnerable to unexpected flare-ups under the intense demands of competition.
That appears consistent with Fritz's experience. The American had previously managed the condition by scaling back his schedule, reportedly missing much of the clay-court season to allow his knee to recover before returning to form during the grass-court swing.
Why Tennis Places So Much Stress on the Knees
Elite tennis requires thousands of explosive movements over the course of a tournament. Players repeatedly sprint, stop abruptly, lunge into low positions and generate force through the legs during serves and groundstrokes.
Unlike an acute ligament injury, tendinitis may not immediately limit movement. Instead, discomfort often builds gradually before suddenly becoming severe enough to affect performance.
The Mayo Clinic notes that athletes frequently continue competing through the early stages of tendon pain. As the condition progresses, however, pain may interfere not only with sports but also with routine daily activities.
In Fritz's case, he acknowledged that the pain emerged only a few games into the match, illustrating how quickly symptoms can escalate under the physical demands of Grand Slam competition.
One of the biggest challenges with tendinitis is that it affects more than pain tolerance.
Sports medicine specialists say tendon pain can subtly reduce an athlete's ability to push off explosively, absorb force while landing and maintain confidence in directional changes. These small deficits may be enough to alter shot selection, movement patterns and reaction time against elite opponents.
For tennis players, that can mean slower court coverage, reduced power generation and hesitation during long baseline exchanges where every fraction of a second matters.
Treating Tendinitis Requires More Than Rest
Although rest remains an important part of recovery, experts no longer recommend prolonged inactivity as the primary treatment for most cases of tendinitis.
Instead, rehabilitation typically focuses on progressively strengthening the tendon through structured loading exercises, particularly eccentric strengthening programs that improve the tendon's ability to withstand stress.
For elite athletes, managing tendinitis is often less about achieving a permanent cure than minimizing recurrence.
Sports medicine experts recommend carefully balancing training loads, allowing adequate recovery between competitions, and monitoring early warning signs before pain becomes severe. Strength training targeting the quadriceps, hamstrings, glutes, and calf muscles may also help reduce excessive strain on the patellar tendon.
Even then, recurrence remains common because tendons adapt more slowly than cardiovascular fitness or muscle strength.
