Walking over hilly terrain helps you burn more calories than sticking to your safe, flat neighborhood sidewalk, but it can also lead to knee pain. When your knee starts hurting every time you tackle that big hill, the pain could be arising from several sources. Check with your doctor just to make sure the pain isn't a symptom of a bigger problem, and stretch your legs well before and after each walk.
Cartilage Issues
Cartilage helps cushion the bones around the knee, including where the kneecap meets the thigh and shin bones. When you consistently put strain on your knees by walking uphill, if your feet don't align properly when walking or if your knee muscles are tight, your can strain or tear the cartilage in your knee. Your doctor can diagnose this problem as patellofemoral pain syndrome, or inflammation around unhappy cartilage, or meniscus tears, with tiny rips in the knee cartilage. Your doctor might recommend over-the-counter anti-inflammatory medication or keeping the knee raised with ice on it.
Trouble With Tendons
Iliotibial band syndrome is a fancy way of saying you hurt a big tendon in your leg. This tendon runs across your hips and down to your knee, and it's the bottom area that gets inflamed as you walk uphill too much or don't stretch properly first. Take a break for a few days, perhaps replacing walking with swimming until the pain eases. Ice can also help, or your doctor might try a corticosteroid shot in your knee to help alleviate the swelling and pain.
Muscle Strains
Walking uphill puts a good bit of pressure on your knees, forcing them to work against gravity to propel your body weight up and forward. Doing this too often can create minute tears in your muscle, straining them to the point that walking uphill is painful. Stretching them thoroughly before and after working out can help, and applying heat can keep them loose and pliable to help alleviate the pain.
It's All Downhill From Here
What goes up must come down, which means you might experience pain going down the other side of the hill as well as when you walk up. Whether the problem is runner's knee or patellar compression syndrome, you might feel dull pain behind your kneecap or sharp pain as you walk downhill. Resting and icing the knee can help, but check with your doctor to help determine the cause, which could be anything from flat feet to weak thigh muscles to misaligned bones in your hips and legs.