(ANN ARBOR) - A combination of COVID-19 test results and contract tracing protocols led the Michigan athletic department to suspend voluntary summer workouts in four sports: Swimming and diving, field hockey, ice hockey and volleyball. The freeze, however, is expected to be short-lived. Ice hockey will resume training later this week and the other programs will start back up again next week. Last Friday, U of M announced that 12 student-athletes and one staff member tested positive following a round of testing conducted July 20-21. According to the latest numbers provided by the university, 729 total tests have been administered since mid-June with 13 positive results produced. "Our medical experts are providing the necessary care and communication to individuals who have tested positive for COVID-19 and those who have come into close contact with someone who has tested positive," the school said in a statement. The football team, which has been spared from the temporary shutdown, began its latest phase of training last Friday. It's a 20 hour week filled with weightlifting, conditioning, meetings and walkthroughs.