It is stipulated that a pitch must go at least two meters off the ground, but no higher than 3.5 meters, just above the height of an average person. More over the ball must be thrown underhand, so that the ball is necessarily slow and should be easy to hit.
慢壘投手所投出的球必須呈圓弧型，其弧型最高點必須至少離地面二公尺，但不可高於三．五公尺，如此球速必慢，應該很容易打到。