In the 100-yard relay our team impressed the reowd with each

In the 100-yard relay our team impressed the reowd with each of the members shaving several second
In the 100-yard relay our team impressed the reowd ,with each of the members shaving several seconds off her own best time.这句话中,后边with each of the members shaving several seconds off her own best time是怎样的句式呢?each of somebody doing sth是固定搭配么?如果不是,为什么用shaving呢?中间的each of the members 是做什么的?