Your tibia needs to rotate 10-15° per step. If it can’t, your knee cartilage pays the price. You sit down for work at 9am. You stand up at 5pm. Your knees sound like gravel under a boot. Coincidence? Not even close. When the knee stays locked in one bent position for hours on end, the tibia, that shinbone sitting inside your knee joint, stops going through its natural rotation cycle. Internal rotation, external rotation, the small spiraling movements that keep the cartilage nourished and the joint surfaces smooth. Without those micro-movements, the joint dries out. Surfaces start catching. And that grinding, popping, crunching sound you hear every time you stand up is your knee telling you it hasn’t moved properly all day. The chain goes deeper than just the knee, though. Prolonged sitting tightens the hip flexors, deactivates the glutes, and stiffens the ankle. All of those feed into how the tibia tracks. So the noise in your knee is really the end of a chain reaction that starts at...