The Association of Racing Commissioners International on Wednesday approved model rules that would tighten the restrictions on using shock-wave therapy and would require racetracks to maintain logs of the people who enter backstretches late at night, according to the organization’s president. The rules pertaining to shock-wave therapy would prohibit any horse from training or racing for 10 days after receiving the treatment, which is ostensibly used to stimulate blood flow to damaged tissue. The rules would also require tracks to maintain a registry of the machines and restrict their use to an approved area of the backstretch, where the treatments would be recorded. Shock-wave therapy is currently regulated in a variety of ways in the 38 different racing jurisdictions in the U.S. The Jockeys’ Guild has been pressing the RCI to adopt a model rule governing the use of the machines because of concerns that the treatments can deaden pain if used close to a race. Violations of the rules would be treated as a “prohibited practice,” which carries a minimum recommended penalty of a one-year suspension under the RCI’s model rules. The rule pertaining to the backstretch would require any visitor to the backside of a racetrack between the hours of midnight and 5 a.m. to log in with the security office. Ed Martin, the executive director of the RCI, said that representatives of state racing commissions also discussed amending a rule that prohibits a horse from receiving a raceday administration of the anti-bleeding medication furosemide within 60 days of racing without the drug. The amendment would eliminate the prohibition to make it easier for owners to consider forgoing the drug on raceday, Martin said. The RCI plans to further discuss the amendment leading up to the next meeting of its model-rules committee in December, Martin said.