Sore knees are a common complaint among road runners. Like paper cups, blisters and PBs, they’re part of every race day. But when are sore knees a normal part of the sport, and when do they signal a more serious problem?

Everyone perceives “normal” differently”, says Torrin Theron, a biokineticist at Mediclinic Winelands Day Clinic, “and it’s sometimes hard to know if what you’re experiencing is soreness or pain”. Soreness often occurs due to muscle fatigue and can peak 24-72 hours post-run, slowly decreasing with recovery. This is a normal response if you’ve changed something in your training or just started a walking or running programme.

But if you feel the following symptoms, it’s best to seek medical advice before returning to running. Take note of pain that is:

  • Immediate and severe
  • Sharp and persistent when resting or active
  • Feels wrong, i.e., it’s not how your body normally responds to activity
  • Continues for more than a week.

Knee pain that’s probably nothing to worry about

“We all know our bodies and capabilities,” says Dr Santa-Marié Venter, an orthopaedic surgeon at Mediclinic Kloof. “If you’re an experienced runner, you’ll know when your body is showing you a red flag.” Early knee pain during a run, for example, is probably nothing to worry about. “That’s usually just a sign that you didn’t stretch or do a proper dynamic warm-up before starting – or that you started too fast,” she says. Stretch, walk, and slowly progress to a jog, and the pain should disappear within half a kilometre or so.

Dr Venter explains that anterior knee pain (on the front and side of your knee) that occurs during a run and continues after you have stopped might indicate:

  • Patellar tendinitis (pain in the tendon that runs from your kneecap to your shinbone)
  • Patellar maltracking (your kneecap shifts out of place as your leg bends or straightens)
  • A weak vastus medialis oblique muscle (a teardrop-shaped muscle that helps move your knee joint and stabilise the kneecap).

All of the above could be caused by overtraining or increasing your mileage too quickly. The best treatment is to rest and take anti-inflammatories. After a week of this, reassess how you’re feeling.

“Medial knee pain (on the inner side of your knee) during or after a run is likely pes anserine bursitis,” she says. This an inflammation of the bursa located between your tibia (shinbone) and three tendons of the hamstring muscle at the inside of the knee. 

“Overtraining, uneven surfaces and muscle imbalances can contribute to this. It can be managed with rest, anti-inflammatories, physiotherapy, and occasionally a cortisone injection into the bursa (a fluid-filled sac or sac-like cavity that prevents friction at the joint).”

Knee pain you need to get checked out

“If you have persistent or severe pain and any of the following symptoms, a visit to the doctor is recommended,” says Theron:

  • Obvious swelling or deformity of the knee joint
  • Inability to bear weight on your knee
  • The knee “gives out” when you try to walk
  • Pain that disrupts your sleep

A fever or temperature in addition to redness and swelling – which could signal an infection.

“Pain on the lateral aspect (outer side) of the knee, which typically starts later during your run and prevents you from running any further due to pain, could be iliotibial band (ITB) syndrome,” says Dr Venter. Resting will make the symptoms disappear completely within a day or two, but it’s difficult to treat. Treatment typically involves:

  • Stretching
  • Abductor rehab – any of the muscles that cause movement of a limb away from the midplane of your body or away from a neighbouring part or limb
  • Kinetic chain strengthening – these exercises target muscle groups at the back side of the body.

“But always consult a sports physician to get appropriate multidisciplinary treatment,” Dr Venter emphasises.

In terms of specific diagnoses, she says persistent pain under the kneecap could be a sign of Chondromalacia patella (unstable kneecap), or fat pad impingement.

Meanwhile, posterior pain (at the back of your knee) that continues after a run could be due to osteoarthritis and an accompanying Baker cyst (a fluid-filled cyst behind the knee).

A knee that suddenly locks or gives way and swells the next day could indicate a meniscus injury. In any of these cases, consult your doctor for a proper diagnosis.

Knee pain that needs urgent attention

A sudden popping sound and immediate swelling of the knee is the trademark of an anterior cruciate ligament (ACL) injury, warns Dr Venter. If this happens, stop running immediately and consult your doctor.

“If your patella dislocates, stop immediately!” she says. “Try to reduce the patella into its normal position. This shows you have a medial patellofemoral ligament (MPFL) injury. This ligament is part of the network of soft tissue restraints that helps stabilise the knee. An MPFL injury always requires surgical intervention.

Whether you’re a serious runner or just an occasional walker, always look after your knees. And if you’re in doubt, see your healthcare professional. “Any knee pain that occurs suddenly and doesn’t improve with a brief period of walking warrants further investigation,” Dr Venter advises.