Most workout-related knee pain comes from muscle imbalances and poor movement patterns, not from the exercises themselves. Squats, lunges, and running are safe for healthy knees when the muscles around the joint are strong enough and firing in the right order. The fix is rarely to stop training. It’s to train smarter: warm up properly, strengthen the right muscles, and clean up your form.
Why Knees Hurt During Exercise
The most common type of exercise-related knee pain is patellofemoral pain, a dull ache around or behind the kneecap. It happens when the kneecap doesn’t track smoothly in its groove as you bend and straighten your leg. Two factors drive this more than anything else: letting your knees drift inward (called knee valgus) and having an imbalance between the muscles on the inner and outer thigh.
In people with healthy knees, a small muscle on the inner thigh (the vastus medialis oblique, or VMO) fires before the outer thigh muscle during movements like single-leg standing. In people with knee pain, that firing order is reversed, and the outer thigh pulls the kneecap sideways. Meanwhile, weakness in the gluteus medius, the muscle on the side of your hip, allows your thigh to rotate inward during squatting and landing. This increases the angle of force on the kneecap and loads the inner portion of the knee excessively.
All squat variations create tension overload on the knee, particularly when the knee is bent between 60 and 90 degrees. That doesn’t mean squats are dangerous. It means the muscles supporting the knee need to be strong enough to handle the load at those angles, and your form needs to distribute that load properly.
Warm Up for at Least 7 to 10 Minutes
A dynamic warm-up before training prepares your joints, activates stabilizing muscles, and increases blood flow to the tissues around the knee. Research supports performing one for at least 7 to 10 minutes, at least twice a week (ideally before every session), using movements that progressively increase in intensity.
Start with light cardiovascular activity like jogging in place or jumping jacks for two to three minutes. Then move into dynamic stretches: leg swings (forward/back and side to side), walking lunges, and bodyweight squats. The goal is to take each joint through its full range of motion without holding static stretches, which can temporarily reduce muscle power. Finish with movements that mirror your workout. If you’re about to squat heavy, do a few sets of air squats and glute activation drills first. This graduated approach reduces the risk of sudden strain when you add load.
Strengthen Your Glutes and Inner Thigh
Strong quadriceps alone won’t protect your knees. The gluteus medius and VMO are the two muscles most responsible for keeping the kneecap tracking correctly, and most gym routines underwork both of them.
When the gluteus medius is weak, it causes the hip to adduct and internally rotate during weight-bearing movements. This increases the inward angle at the knee and pushes the kneecap laterally. Over time, it can also cause the iliotibial band on the outside of the thigh to tighten, adding further lateral pull. Strengthening the gluteus medius directly improves functional knee scores and reduces pain, even in people recovering from knee surgery.
For the VMO specifically, hip adduction exercises are effective because the VMO’s muscle fibers connect to the tendons of the inner thigh muscles. Exercises that combine knee extension with hip adduction (like a bridge with a ball squeezed between the knees) produce a more balanced activation ratio between the inner and outer thigh compared to simple leg extensions. Performing squats with a light isometric squeeze inward at the knees also increases gluteus medius activity by challenging pelvic stability.
Practical exercises to add to your routine:
- Side-lying hip abduction: 2 to 3 sets of 15 reps per side, focusing on the top of the hip rather than swinging the whole leg.
- Glute bridges with a ball squeeze: Place a small ball or pillow between your knees and squeeze while lifting your hips. This activates both the glutes and VMO simultaneously.
- Single-leg Romanian deadlifts: These challenge the gluteus medius to stabilize the pelvis on one leg, directly training the pattern that protects the knee during lunges and running.
- Terminal knee extensions with a band: Loop a resistance band behind the knee and straighten the last 30 degrees. This isolates the VMO at the end range where it’s most needed.
Fix Your Squat and Lunge Form
A healthy squat or lunge should use roughly 60% quadriceps and 40% glutes. When knee pain shows up, it’s usually because you’re loading the quads far more than the glutes, often because of two correctable form errors.
The first is letting your knees travel too far forward past your toes. A systematic review of squat studies found that when the shin line moves in front of the toes, stress on the patellar tendon increases by about 18.8% compared to 11.5% when the shin stays behind that line. This doesn’t mean your knees can never pass your toes, but if they’re doing so excessively, you’re putting unnecessary pressure on the front of the knee. The cue “press down through your heels to stand up” shifts the load backward into the glutes and hamstrings.
The second error is knee valgus, where your knees collapse inward. This puts excess load through the front and inside of the knee. A useful cue is to imagine spiraling your thighs outward so your knees track toward your pinky toes throughout the movement. You don’t need to push your knees way out, just keep them aligned over the outer edge of your foot. If you can’t maintain this alignment with a given weight, the weight is too heavy for your current stabilizer strength.
Choose the Right Footwear
Your shoes affect how much force reaches your knees with every step and every rep. For runners dealing with knee pain, two shoe features matter most: cushioning and heel drop.
Cushioning absorbs impact so your joints don’t have to. Shoes with higher shock absorption redirect stress away from the knees and into the lower leg muscles, foot, and ankle, which are better equipped to handle it. If you run and experience knee pain, prioritize shoes with substantial midsole cushioning rather than minimalist designs.
Heel drop, the height difference between the heel and forefoot of the shoe, has a direct relationship with knee stress. A study of 18 runners found that shoes with a heel drop of 10 mm or 15 mm increased peak patellofemoral joint stress by more than 15% compared to zero-drop shoes. This is because a higher heel encourages a heel-striking pattern that increases the extension force at the knee. Aim for a heel drop of 8 mm or lower if knee pain is a concern. Lower-drop shoes shift more work to the calves and Achilles tendon, so transition gradually if you’re used to traditional running shoes.
If you have flat feet, look for shoes with arch support. Without it, the foot rolls inward excessively during each stride, and that rotational force travels up the chain into the knee joint.
When Knee Sleeves Actually Help
Neoprene knee sleeves don’t add structural support the way a rigid brace does, but they do improve proprioception, your body’s sense of where your joint is in space. This matters because better proprioception means better muscle activation and more precise movement control.
Research on knee sleeves found that people who already have good joint position sense don’t benefit from wearing a sleeve when they’re fresh. But after a fatigue protocol (simulating the later portion of a workout), all subjects showed improved proprioceptive accuracy when wearing a sleeve. If your knee pain tends to show up toward the end of a session when your muscles are tired, a knee sleeve may help you maintain better control and reduce sloppy mechanics. People with naturally poor joint awareness benefit from sleeves even before fatigue sets in.
Knee sleeves are a useful tool, but they’re supplemental. They won’t compensate for weak glutes, poor form, or skipping your warm-up.
Pain Signals You Shouldn’t Ignore
Some knee discomfort during a new exercise program is normal as tissues adapt to unfamiliar loads. But sharp pain, pain that increases during a set rather than fading, or pain accompanied by swelling or a feeling of instability are signals to stop the exercise immediately. A dull ache that appears the day after training and resolves within 24 hours is generally a sign of tissue adaptation. A dull ache that lingers for days, worsens with stairs, or shows up every session in the same spot suggests a movement pattern or load problem that needs to be addressed before it becomes an injury.
The simplest rule from the American Academy of Orthopaedic Surgeons: you should not feel pain during an exercise. Discomfort from effort is one thing. Pain in the joint itself is your body telling you something about the movement, the load, or the muscle balance isn’t right.