New cells must replace damaged cells to maintain bone health. This requires increased activity of osteoblasts, and thus osteoblast apoptosis is also increased in athletes. So far - so good. This extra calcium can only be temporarily stored in the bones if it can precipitate on pre-calcified bone matrix which osteoblasts composed for this purpose. This calcium will subsequently be deported to be excreted because it is redundant calcium that is being temporarily absorbed for the sole purpose of preventing elevation of the blood-calcium level.
Redundant calcium is deported according to the body's designed plan for the bones.
T he loading on bones is so intense in athletes that maximum capacity of osteoblasts to compose new bone matrix is met. A small percentage of the total bone cells is damaged every training session. If remaining undamaged cells must compose new matrix to absorb redundant calcium, their osteoblasts will not be able to keep up with composing new matrix the next day when the cells are damaged due to loading. In athletes, especially, it is essential to prevent any unnecessary processing of calcium. This means that the athletes should not absorb any more calcium than they need to maintain bone-health.