AMES, Iowa (AP) — The absence of Iowa State senior running back Shontrelle Johnson hasn’t slowed the Cyclones down at all this spring.  Iowa State finds itself with a problem many other programs wish they had as spring ball winds down. The Cyclones run six deep at tailback — assuming that Johnson’s recovery from an ACL tear goes smoothly — and each of them has done enough to excite the coaching staff. Iowa State wraps up spring practice with an intra-squad scrimmage Saturday at Jack Trice Stadium.