Let’s get this out of the way: running won’t ruin your knees, no matter what your smug, sedentary co-worker says. “There are three large studies that show long-term endurance running doesn’t seem to affect joint health,” says Dr Richard Willy, an assistant professor of physical therapy at East Carolina University in the US.
In fact, runners may have healthier joints than their inactive counterparts, says Dr Max R. Paquette, an assistant professor of biomechanics at the University of Memphis. It’s well known that weight-bearing exercises such as running strengthen bone and muscle, and it’s believed that they might do the same for cartilage, the tissue that cushions joints. And strong muscles – built by running and strength-training – support joints so they are less vulnerable to injury.
Yet there’s a condition called ‘runner’s knee’ for a reason. Patellofemoral pain (knee pain) is the most reported injury in the sport. Hip, ankle, and foot injuries happen too. But not because someone is running – it’s because he or she is running with flawed form or muscle imbalances. So while you can rest assured that running is healthy for your entire body – joints included – it’s important to learn what causes joint pain. Taking steps to minimise the risk can help you keep running into your golden years.
Common ailments that sideline runners
HIP, KNEE, ANKLE, FOOT
The ‘wear-and-tear’ condition that occurs when cartilage breaks down over time. Blame genetics and biochemical responses (not necessarily running).
This friction syndrome is caused by inflammation of the bursa – the small sac of fluid that lubricates the muscles and tendons that run around the hip joint.
● Patellofemoral pain (a.k.a. ‘runner’s knee’)
Discomfort behind the kneecap (patella) caused by repetitive contact between the underside of your patella and your femur (thigh bone).
● Patellar tendinopathy
Inflammation of the tendon that runs from the kneecap to the top of the tibia (one of two lower leg bones). The pain usually occurs at the bottom of the patella, especially when running downhill.
● Torn meniscus
Cartilage on the inside and outside of the knee acts as bumpers between the femur and tibia. As you age, it becomes thinner and more susceptible to damage.
● Achilles tendinopathy
One of the most common sources of ankle pain, caused by inflammation of the largest tendon in the ankle.
● Ankle sprain
When the foot and ankle turn in or out suddenly, the ligaments that stabilise the ankle joint can become damaged.
● Bunion Under repetitive pressure, the big toe joint can move out of place, swell, and turn inward, causing a painful, bony protrusion.
WHY DOES MY KNEE ACHE?
Probable causes of the pain
Willy says hip adduction – when the thigh moves inward from the hip mid-stride, causing a knock-kneed effect – is one of the most common sources of biomechanical-related knee pain. Overstriding is another.
This is intricately related to biomechanics, since muscle imbalances can cause poor biomechanics – and conversely, poor biomechanics can result in imbalanced muscle development. If you can’t do a single-leg squat without wobbling or having your knee dive in or out at a steep angle, you may have some glute or hip weaknesses that need attention, says Dr Keith Spain, a sports-medicine specialist at the Orthopaedic Group.
While the link between running injuries and genetics is still unclear, Spain says that arthritis has a genetic component. “If your parents had arthritis, you’re more likely to have it,” he says. And while of course age is a factor, Spain says that getting old doesn’t necessarily mean you’ll get arthritis. “I see 80-year-olds without any arthritic changes, and 50-year-olds with terrible arthritis.”
Women are twice as likely to report knee pain as men, Willy says. But researchers aren’t entirely clear on why. “The hypothesis has been that women’s lower-extremity alignment places the knee in a position where it’s more susceptible to injury; I think there’s more to it than that, though,” says Paquette, adding that subtle differences in women’s connective tissue make-up may also play a role. Pregnant women or women who have just given birth are also more susceptible to joint injuries, because ligaments relax to prepare for childbirth.
Pain is something researchers are still working to understand better, says Willy, adding that joint-related pain seems to be individual. “Two runners with the same biomechanics can go through the same training programme, and one gets injured but the other doesn’t,” he says. “We really don’t know exactly why that happens.” He says that variables such as sleep quality, nutrition, and even psychosocial factors – such as fear of getting injured – may contribute.