Jumping - Daily Functioning of the Knee

Jumping
It’s hard not to feel a twinge of envy when you watch your favorite six-year-old leap off the furniture, knowing the only damage she’s likely to cause is to Mom’s favorite breakable. As we get older, the impact of jumping is likely to have far more painful consequences than paying for repairs out of our allowance money. The harsh impact combined with the potential for twisting and tearing, makes jumping a risky business indeed. Still, some of us can’t resist. We rise into the air on driveway basketball courts and in funk-music-driven aerobics classes. Sometimes we land easily, sometimes we don’t.

When you jump, even a good landing may compromise your knee joint. Those strong quadriceps muscles contract on landing and pull hard at the patellar tendon’s insertion on the tibial tuberosity (the little bump at the top of the tibia). This may cause jumper’s knee (inflammation of the patellar tendon). Of course, if you land off your intended, balanced course, you will strain all elements of your knee joint. The correct shoes and corrective knee bands can reduce knee injury when jumping.

Stair Climbing - Daily Functioning of the Knee

Stair Climbing
Once used primarily by athletes in training, stair climbing has become popular with exercisers who take step classes in gyms and with aerobic enthusiasts who use the outdoor stairs at beaches, hills, and high school or college stadiums. A lot of them end up limping into the doctor’s office with knees that just can’t take the strain. With stair climbing, the knee moves quite a bit and is under a great deal of pressure. The more the knee is flexed, the tighter the patellar tendon is stretched, pushing on the patella. When the tendon stretches out, the area where it attaches becomes inflamed, and tracking of the patella goes off course. It drifts, slips, and tilts, resulting in patellofemoral syndrome (runner’s knee) or, in more extreme cases, chondromalacia patellae (wearing out of the cartilage on the back of the patella). Extreme wear and tear on the cartilage and menisci (the cushioning discs between the femur and the tibia), over time, roughen the glassy cartilage surface and decrease the protection it and the menisci offer. Eventually, bone may meet bone, causing painful arthritis. Stair climbing may increase the force of the patella on the femur up to four times body weight. To help keep the exercise as safe for your knees as it is good for your metabolism and cardiac function, take care to give your knees a rest (don’t do the same exercise two days in a row), alternate stair climbing with other types of exercise, reduce your speed while climbing, and pay immediate heed when your knees start to ache or swell.