Riding a bike is one of the lowest-impact cardio exercises that you can do. However, knee pain amongst cycling enthusiasts is still a fairly common problem. Because of this many people believe that cycling is bad for your knees, but that might not be the case.
There are other factors that could be causing you knee pain. It may only occur whilst you’re cycling, and the issue might stem from your technique and equipment set-up.
Unbalanced Leg Strength

There is no denying that cycling is a repetitive motion, and if you don’t have sufficient leg strength you can overwork the knees and bring on injury.
But, if cycling is the only exercise you get, there is potential that your leg muscles will be out of balance, with over developed quads and underdeveloped glutes and hamstring.
This imbalance can also increase the stress on your knees, therefore cyclists will benefit from training all of the muscles in their legs as they help to stabilise the knee joint.
Ensure you warm up properly
Before you head out on a gruelling ride, you should always ensure to warm up properly. Even if you only ride your bike on a short commute to work, it’s always worth warming up.
You don’t have to necessarily stretch a lot before riding. Starting at a lower pace, and low gear will help you warm up the knees and leg muscles before you head off at higher speeds.
Having a properly fit bike

You should never overlook the importance of having a properly fit bike when you are looking at purchasing a bike.
If you have a bike that is too small, or large it can affect how much your knees have to bend whilst pedalling.
A seat that is at an optimal height will put your knee in roughly a 45 degree angle at the top of the stroke. And leave a slight bend in the knee whilst at the bottom of the stroke.
Your pedals also need to be placed the correct distance/width away from the bike. Pedals that are too close or far away from the frame can also cause knee pain.
You should be able to comfortably center your feet on the pedals, or strap your feet in whilst pointing forward without any pain or feeling of twist in the knee joints.
Try an alternative style of bike
Unfortunately age-associated wear on the knee joints, weight issues, or past injuries will cause knee pain whilst cycling regardless of the precautions you take. If this sounds like your situation, and you love cycling, you could potentially switch to a different style of bike.
Recumbent bikes are common in gyms, they allow you to lean backwards whilst cycling, and help to take the pressure off your knee joints. There are also some manufacturers that sell recumbent bikes for outside riding.
Conclusion
So, is cycling bad for your knees? Not on a whole. Especially when the correct precautions such as warming up, training properly and you get fitted for your bike. Your legs can rotate over 5000 times per hour whilst cycling. So it is extremely repetitive on the knee joints, but shouldn’t cause an issue for most.