Why Quad Strength is Crucial for Knee Health

If you’re a fitness-forward athlete—whether you’re into CrossFit, Olympic lifting, endurance running, or just crushing it in the gym—you’ve probably felt that familiar twinge of knee pain. Maybe it shows up during box jumps. Maybe it’s a sharp sting during the descent of a squat. Or maybe it creeps in mile after mile during your long runs.

No matter when it shows up, knee pain can sideline even the most disciplined athletes. But the root cause often isn’t the knee itself.

As a fitness forward physical therapist team in Minneapolis working with everyone from runners to barbell athletes, we’ve seen firsthand how different aspects of load intolerance in the quads can set the stage for patellar tendonitis, runner’s knee, and persistent knee pain when squatting. Let’s break down why quad strength is so essential for knee health—and what you can do about it.

The Knee Joint: More Than a Hinge

The knee is a complex structure relying heavily on muscular support. It absorbs force, stabilizes your movements, and powers your plyometrics—whether that’s driving out of the bottom of a heavy squat or bounding through double-unders.

Your quadriceps, a group of four muscles on the front of your thigh, play a vital role in:

• Controlling deceleration (important in box jumps and downhill running)

• Supporting the kneecap (patella) to glide smoothly in its groove

• Absorbing impact to protect the joint and tendons

• Providing power for knee extension during running and lifting

If your quads aren’t pulling their weight—literally—the result is often compensatory stress on your patellar tendon and surrounding structures. That’s when the aches can start to show up.

Common Quad-Related Knee Conditions

1. Patellar Tendonitis (Jumper’s Knee)

Seen often in CrossFit athletes as well, this condition arises from repetitive jumping and squatting. Weak or fatigued quads force the patellar tendon to overwork, resulting in pain just below the kneecap.

2. Runner’s Knee (Patellofemoral Pain Syndrome or PFPS)

Frequent in long-distance runners, this is multi factorial and commonly blamed as a knee issue. Though there is a strong correlation to the hip here as well, we often see a combination of hip and quad imbalances or weakness affecting PFPS.

3. Knee Pain with Running or Squatting

Whether it’s a 5K or a heavy barbell snatch, poor quad engagement increases joint stress and reduces stability—often resulting in pain during dynamic movement.

The Quad Check: Are Yours Doing Their Job?

Ask yourself:

• Do you feel your quads working during squats, or is it all glutes and hamstrings?

• Do your knees ache more after running downhill or doing lots of double-unders?

If you answered “yes” to the above, your quads may need a strength tune-up.

How to Build Quad Strength for Knee Longevity

You don’t need to overhaul your program—just make sure your training is smart and quad-focused. Here’s how:

1. Quad-Dominant Strength Work

Incorporate movements like:

• Front squats

• Split squats (rear foot elevated for added demand)

• Wall sits and tempo squats (slow on the way down)

• Spanish squats (great for quad isolation without knee shear)

2. Eccentric Training

Controlled lowering in exercises helps build tendon resilience and quad control, which is especially important for addressing or preventing patellar tendonitis.

3. Address Mobility Restrictions

Tight hip flexors, quads, or limited ankle dorsiflexion can all alter squat mechanics and place more stress on the knee. A good physical therapist, like ours here in Minneapolis can evaluate and guide you on individual mobility needs.

4. Train in isolation

This movement has been a hot topic of conversation for a long time, but terminal knee extension drills and long arc quads under proper high to moderate loads are great for targeting it.

Don’t Let Knee Pain Be the Norm

Knee discomfort isn’t something you need to “tough out.” Whether it’s knee pain when squatting, pain with box jumps, or knee pain with running, the solution often lies in smart, targeted quad training. If you’re consistently pushing your limits—CrossFit-style, on the trails, or in the weight room—your knees need strong quads to keep up.

If you’re dealing with chronic pain or unsure where to start, reach out to a physical therapist in Minneapolis who understands the unique demands of athletes like you. Quad strength isn’t just about performance—it’s about staying in the game for the long run.

Ready to get ahead of your knee pain? Book a movement assessment or quad strength screen with a fitness-forward PT today and start feeling the difference in every step, squat, and stride.