Forget about being explosive to make the save, by the time the shot comes, the keeper who has too much bend either ends up falling forward as he goes to make a play on the ball or is dropping back on his heels from fatigue. Chest and arms are next as we move up and probably the area where there is the most variation in the ready position. The keeper wants to keep his chest above, or in front of his knees. This allows him to keep his weight forward. By also keeping his hands and arms in front of him, the keeper further reinforces keeping his weight forward while maintaining balance.
Some coaches prefer keepers to play with their hands out to the side.
This allows the keeper to take up more space, but the ready position isn't completely about taking up space. With his hands out to his side, as opposed to in front of him, the keeper has a harder time moving forward to the shot and maintaining balance. As a result, he might make the save, but often is off-balance if there is a rebound. A good example of the ready position from the side, weight is on the balls of the feet, with knees, chest and head forward. Examples of the ready position head on.