Why Do Tennis Players Have Bad Knees?

The brutal reality behind a graceful-looking sport

Honestly, if you’ve ever played tennis for more than just a couple of casual rallies, you probably get it. From the outside, tennis looks elegant—those smooth strokes, quick footwork, clean serves. But underneath that grace is a hell of a lot of wear and tear, especially on the knees.

I remember talking with my friend Mike, who used to compete at college level. We were both in our late twenties, and he was already talking about cortisone shots and “pre-hab” (yes, pre-habilitation, not even rehab). That’s when it hit me—tennis is brutal on the knees, and it's more common than people think.

Let’s break it down and see why those green courts leave so many knees aching.

Sudden stops, starts, and slides: a recipe for joint disaster

Constant deceleration and explosive movement

Tennis is all about explosive movement in short bursts. You sprint, stop, change direction, lunge, recover—and repeat, sometimes for hours. Every time a player slows down or pivots, the knee absorbs a ton of force.

Unlike running or swimming, which are more linear and repetitive, tennis throws your joints into chaos. There’s no rhythm. It’s stop-go madness with intense lateral (side-to-side) pressure, which your knees aren’t exactly built to love.

A physio once told me it’s like putting your car in full throttle, slamming the brakes, then turning sharply—hundreds of times per match. Eventually, something gives. Usually cartilage or ligaments.

Hard courts make it even worse

Let’s talk about surfaces. Clay is forgiving. Grass is gentle (though slippery). But hard courts? Absolute knee killers.

They don’t absorb much shock, so every impact from a jump, sprint or slide sends the force right back into your joints. Think concrete disguised with a little paint and polish. And since a lot of amateur and even pro tournaments are played on hard courts (hi, US Open), the knees just take hit after hit.

Common knee injuries in tennis (and why they stick around)

Patellar tendinitis: the dreaded “jumper’s knee”

This one is super common. It’s basically inflammation in the tendon connecting your kneecap to your shinbone. It’s the kind of pain that starts dull, gets sharp when you lunge or jump, and eventually just doesn’t go away.

My cousin tried to push through it for months. Big mistake. By the time he saw a doctor, they were already talking about a six-month break. Rest, rehab, repeat. And even then, he said it never quite felt the same.

Meniscus tears and cartilage wear

These are the “silent killers.” You don’t always feel them right away. But every time you twist your knee awkwardly or land a bit off—boom, tiny damage. Over time, that adds up. And unlike muscles, cartilage doesn’t really heal.

That’s what makes it so scary. You’re 25, you feel fine, and suddenly one day you wake up and can’t bend your knee without it clicking or swelling. I’ve seen it happen.

ACL and MCL strains

More rare, but still real. Especially during an off-balance pivot or awkward landing. It’s not just the pros who deal with this. I’ve known weekend warriors who went for a backhand and ended up needing surgery. Wild.

The volume of play and lack of recovery

Tennis isn’t seasonal—your knees never get a break

This isn’t football, where you have a clear off-season. Tennis is year-round. Between tournaments, training sessions, conditioning… it never stops. Overuse is a killer, especially when rest is basically considered a luxury.

Even junior players are clocking insane hours. I coached a teen once who played 20+ hours a week. Her knees were already hurting at 16. She thought that was “normal.” (Spoiler: it’s not.)

The culture of playing through pain

Let’s be honest: there’s this unspoken rule in tennis that “if it’s not broken, play through it.” But that mindset often leads to chronic injuries. Little tweaks become lingering problems. Before you know it, ice packs become part of your routine, like tying your shoes.

And yeah, I’ve been guilty of it too. "It’s just sore." "It’ll loosen up after I warm up." Sound familiar?

Are there ways to protect the knees?

Strength training and mobility work

Absolutely. Tennis players today do a ton of off-court training focused on strengthening the glutes, hamstrings, quads, and core—basically building a support system around the knee. Balance work, mobility, and stretching also help a lot.

When I finally started squatting and doing single-leg exercises consistently, I noticed a real difference. Less stiffness. Less post-match soreness. More confidence pushing off my right leg (my weaker side).

Smarter scheduling and rest

Taking breaks. Cross-training. Even playing on softer surfaces when you can—these things help more than most people admit. But they’re not sexy, so they’re easy to skip. Trust me, your 40-year-old knees will thank you if you listen now.

Better shoes, better habits

Wearing court-specific shoes, replacing them before they wear out, using orthotics if needed—it all matters. One of my teammates once solved his knee issues just by switching shoes. No joke.

Final thoughts: it's not hopeless, but it's real

So… why do tennis players have bad knees? Because the sport demands a lot—more than most bodies can handle long-term without serious maintenance.

Tennis is beautiful, yeah, but behind every smooth forehand is a knee that’s been through hell and back. If you play, take care of yourself. Learn from the mistakes we’ve all made. You don’t have to quit. But you do have to get smart.

Your knees aren’t invincible. But they can go the distance—if you give them a fighting chance.

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