On a TWO or FOUR person bobsled team, what is the athlete in front AND the athlete in the back called?

The one at the front is the driver. he one at the back is the brakeman.

Explanation:

In either a two or a four person bobsled team, the one at the front of the sled is called driver. The one at the back is called the brakeman, and is the one that pushes the back of the sled. The brakeman is the one that jumps in last as the sled gains speed.

In case of the four person, the other two team participants are just referred as riders.

the ima (higher than 1m) will be greater than the ima with the height of 1m.