exercise such initiative as fall within their sphere

exercise such initiative是一个短句,fall within their sphere也是一个短句.
其中fall within是“属于……的范围”的意思.
例句：Spend by each department have to fall within certain parameter.
这里面的fall within their sphere是用来补充exercise such initiative的意思,即不是在其他人的范围内,而是他自己的范围内的发挥主动性.
你可能是断句断在了initiative后面,变成了把as fall看成了一个连在一起的成份了,才会弄不清楚这个fall到底什么意思吧.