Runner in Motion (1909)

Schmidt, next at bat, gave the hit-and-run sign, with both runners in motion, hit a hard bounder down toward third base where Tannehill of Chicago was playing.Daily Argus-Leader (Sioux Falls, SD), August 25, 1909, p4 

Earlier example of term without sense or runners leaving at the pitch:
— “Corcoran set the runners in motion by lively single to right….Pittsburgh Daily Post, July 31, 1890, p6

No earliest use given in Dickson Baseball Dictionary