Human knees are built to walk and run on natural terrains, which is why, using a treadmill can have bad effects in the long run, warns Dr Rajeev K Sharma

It’s needless to say that exercising is a crucial part of a healthy regimen and fitness enthusiasts go to any length to keep their bodies in the best of shape and health. For many people, treadmill is an important part of their workout regimen as it allows them to get an aerobic workout indoors and entails all the health benefits of running. It would burn calories faster than most other forms of indoor exercise, it would keep your heart healthy, and reduce the risk of diabetes. However, despite all its benefits, it may not be all that good for your knees. In fact, an excess of treadmill exercise can even damage your knee joints in the long run.

Knee is one of the most complicated joint of the body which bears almost all its weight and is most susceptible to injury and arthritis. An optimum exercise could help keep your knees in good health but at the same time too much of it can be harmful for its ligaments and cartilage. It may cause wear and tear. Running itself is considered as high impact activity (activities which put extra pressure on your knees) for your knees, but when it is done on treadmill, it becomes even more vigorous.

In fact, there is an entire set of medical conditions that are attributed to high impact activities which cause pain around the front of the knee (patellofemoral pain), knows as Runner’s Knees. These conditions include anterior knee pain syndrome, patellofemoral malalignment, and chondromalacia patella. Runners, jumpers, skiers, cyclists, soccer players and others who frequently put strain on their knees, often suffer from Runner’s Knees.

This explains a little why running on a treadmill for long periods can damage your knee. Running on a treadmill is sort of alien to your intricate knees, innately designed to walk or run on the earth. So when you run on a treadmill, and try to match the speed of the machine, the point contact pressure tends to remain on a very limited area of the knee which is repeated every few seconds. On the other hand, when you are run on a track or on grass, apart from changing your position constantly you also do not try to match the speed of a machine. Changing your position continuously facilitates the persistent change of point contact area on your knee and therefore cuts the chance of wear and tear.
So, if you are running on a treadmill for half an hour plus time, you are perhaps not doing the right thing. It might not have immediate consequences, but over a period of time, it may start having bad effects on your knees.

While exercising is a very good way to keep your body and joints active and healthy, excessive exercising that tests the limits of your body’s strength can sometimes have negative effects. The key is to start with moderate levels and increase the levels of your exercise regime slowly. But never do it beyond your body’s capacity. So, better run out in the open field rather than endangering your knee on a treadmill. Even if you have to run on a treadmill, do not overdo it; do it for shorter spans of time.

(The writer is a Senior Consultant Orthopedics & Joint Replacement Surgeon)