From Andre Agassi to Venus Williams: Tennis legends who battled medical conditions their whole careers

Tennis is often a test of mental grit and physical durability. But for some of the greatest players in the sport's history, the challenge went far beyond the court. These athletes not only faced down top competition — they did it while managing serious, lifelong medical conditions that had nothing to do with injury or tennis itself. Their triumphs are a testament not just to talent, but to resilience, discipline, and sheer will.

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Rafael Nadal – Müller-Weiss Syndrome

Diagnosed: In 2005 (age ~19)

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For Rafael Nadal, pain has been a constant companion. Diagnosed in the mid-2000s with Müller-Weiss syndrome, a rare and degenerative condition affecting a bone in the midfoot, Nadal competed his entire career with this chronic issue. It first surfaced around 2005, just as he was taking the tour by storm as a teenager.

Despite the condition — which often causes debilitating pain and even leads to early retirement in other athletes — Nadal managed it through custom insoles, anti-inflammatories, and nerve-deadening treatments. His dominance on clay, and 22 Grand Slam titles, came not despite this condition, but while living with it daily. He once said, “I have a chronic injury which has no treatment. That's part of my life” (via CNN in May 2022).

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Alexander Zverev – Type 1 Diabetes

Diagnosed: At age 3 (early childhood)

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Few knew that Alexander Zverev, the 6’6” powerhouse from Germany, had been fighting a far more personal battle since childhood. Diagnosed with Type 1 diabetes at the age of 3, Zverev only revealed it publicly in 2022 — after over a decade on the pro tour.

Unlike Type 2 diabetes, this autoimmune condition requires constant management of insulin and blood sugar levels. Zverev has to check his glucose during matches and adjust insulin accordingly, sometimes even mid-tournament. He now serves as an advocate, showing young diabetic athletes that an elite sports career is still within reach.

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Venus Williams – Sjögren’s Syndrome

Diagnosed: 2011 (age 31)

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In 2011, just before the US Open, Venus Williams shocked the tennis world by withdrawing from the tournament and revealing a diagnosis of Sjögren’s Syndrome, a chronic autoimmune disorder that causes fatigue, joint pain, and dry eyes/mouth. But signs had been present long before the official diagnosis — mysterious dips in energy, inconsistent results, and unexplained illnesses.

Despite the toll it takes, Venus didn't hang up her racket. She reworked her diet, training, and scheduling, and returned to play for over a decade more, reaching Slam finals even into her late 30s. Her perseverance with a condition known to drain energy is nothing short of heroic.

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Pete Sampras – Thalassemia Minor

Diagnosed: As a teenager (private until late career)

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Pete Sampras was famously stoic — a champion who never wore his emotions (or his exhaustion) on his sleeve. But behind that calm façade was a condition he kept private for most of his career: β-thalassemia minor, a genetic blood disorder that results in mild anemia and chronic fatigue.

Diagnosed in his teens, Sampras played his entire career managing lower-than-normal energy levels. Long matches, extreme heat, and back-to-back events took more out of him than the average player. Yet he still managed to finish as year-end World No. 1 six years in a row, winning 14 Grand Slam titles along the way.

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Andre Agassi – Spondylolisthesis

Diagnosed: Late 1990s (chronic symptoms throughout career)

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Andre Agassi's back pain wasn’t just the typical wear-and-tear of a long career — it was the result of spondylolisthesis, a condition where a vertebra slips out of alignment, often causing nerve pain and stiffness. While his official diagnosis came in the late 1990s, he had been struggling with back issues for years.

Agassi played much of his prime — and even staged his late-career resurgence — while receiving regular cortisone injections and managing constant pain. The fact that he won his last Grand Slam at age 32, and remained competitive into his mid-30s, is even more remarkable in that context

These five legends didn’t just fight through tough matches — they fought through bodies that demanded more than their rivals ever knew. Their achievements shine brighter knowing they were often playing at less than 100%, yet still found a way to dominate.

They prove that greatness isn’t just about power and precision — it’s also about perseverance.