Knee pain is the number one overuse injury in cycling. It accounts for roughly 40-60% of all cycling-related complaints. And in almost every case, the cause is mechanical — a fit issue, a training error, or both. Not a structural knee problem.
That's the good news. Mechanical problems have mechanical fixes.
The 5 Most Common Causes
1. Saddle Too High
Symptoms: Pain behind the knee (posterior), especially on the downstroke. Often worse at the end of long rides when fatigue sets in.
What's happening: When your saddle is too high, your leg overextends at the bottom of each pedal stroke. The hamstring tendons and structures behind the knee are being pulled beyond their comfortable range on every single revolution. Over 90 RPM for 2 hours, that's roughly 10,800 repetitions of an overextended joint.
The fix: Drop your saddle 5mm. Ride for a week. If pain improves, you've found your answer. If not, drop another 5mm. The general rule: at the bottom of the pedal stroke, your knee should have a slight bend (roughly 25-30 degrees). If your hips rock when you pedal (visible from behind), your saddle is definitely too high.
2. Saddle Too Low
Symptoms: Pain at the front of the knee (anterior), around or below the kneecap. Often sharp during climbing or high-effort work.
What's happening: A low saddle means your knee is excessively bent at the top of the pedal stroke. This compresses the patella (kneecap) against the femur and overloads the quadriceps tendon. The harder you push (climbing, threshold efforts), the more compression occurs.
The fix: Raise your saddle 5mm. Front-of-knee pain that worsens with intensity is the textbook sign of a saddle that's too low.
3. Cleat Position Too Far Forward
Symptoms: Pain under the kneecap or at the front of the knee, combined with hot foot or toe numbness.
What's happening: When cleats are too far forward, the ball of your foot sits directly over or ahead of the pedal axle. This lengthens the lever arm at the ankle, increasing the load on both the calf and the quadriceps tendon. The knee compensates by absorbing force it shouldn't.
The fix: Move your cleats back 5-10mm. The ball of your foot should sit slightly behind the pedal axle, not over it. This shifts load from the knee to the larger glute and hamstring muscles. Use our Bike Fit Guide for the full approach.
4. Too Much Too Soon
Symptoms: General knee soreness that comes on after increasing training volume or intensity rapidly. Not localised to front or back — more of a dull ache throughout the joint.
What's happening: Your muscles adapt to training load faster than your tendons and connective tissue. When you ramp volume by more than 10% per week or suddenly add high-intensity work (especially hill repeats or low-cadence grinding), the tendons around the knee can't keep up.
The fix: Follow the 10% rule — don't increase weekly volume by more than 10% per week. When adding new types of training (particularly low cadence torque work), start conservative and build over 8 weeks. If you've increased too fast, reduce volume for a week, then rebuild gradually.
5. IT Band Syndrome (Outer Knee Pain)
Symptoms: Sharp pain on the outside of the knee, usually starting 20-30 minutes into a ride and worsening if you continue.
What's happening: The iliotibial band (IT band) runs down the outside of your thigh and crosses the knee joint. When it's tight or irritated — often from excessive internal rotation at the foot, poor saddle fore-aft position, or weak hip stabilisers — it creates friction at the knee with every pedal stroke.
The fix: This one usually needs a multi-pronged approach. Foam roll the IT band and outer quad. Strengthen your hip abductors (clamshells, side-lying leg raises). Check that your cleats aren't forcing excessive internal rotation. A professional bike fit is strongly recommended for persistent IT band issues. Strength training for cyclists addresses the underlying hip weakness.
When to See a Doctor
If knee pain persists for more than 2 weeks after addressing the mechanical causes above, see a sports physiotherapist. Persistent pain despite correct fit, appropriate training load, and proper strength work may indicate a structural issue that needs diagnosis.
Key Takeaways
- Knee pain in cycling is almost always mechanical, not structural — fit and training are the usual culprits
- Pain behind the knee: saddle too high — drop 5mm and reassess
- Pain in front of the knee: saddle too low or cleats too far forward
- General soreness after volume increase: too much too soon, follow the 10% rule
- Outer knee pain: IT band syndrome — foam rolling, hip strengthening, fit check
- When adding low cadence training, progress gradually over 8 weeks to protect connective tissue
- Use our FTP Zone Calculator to ensure training intensity is appropriate
- Persistent pain beyond 2 weeks warrants a sports physio visit
- A targeted stretching routine addresses the tightness patterns that contribute to knee issues
- Recovery strategies help manage inflammation between rides
- If you're coming back after a break, progress extra carefully with the 10% rule
