Question

Some people in old age complain of stiff joints. What do you think could be a possible reason for it?

Answer 1

Old people complain about stiff joints, because of their less strength, loss of CaPO4(calcium phosphate) which make their bones weak. Mostly the critical joints have some of the lubricants which make them to loose the joint pain and mostly due to the reduction of this lubricant they may feel pain. It also due to old age.    

Answer 2

The free movement of joints are because of synovial fluid. As the people get older the fluid disintegrates and the friction btwn the joints are increased causing pain.