might arise. They also observe the condition of other support personnel and are alert for signs of fatigue, overexposure, and heat exhaustion. The physical fitness test has been shown to be a poor predictor of job task performance. The test consists of the following carried out in the order given: Swim 500 yards (or 450 m) utilizing only combat side stroke or breast stroke within 12 minutes 30 seconds (candidates are allowed to push off the sides when turning. However, if the candidate uses the bottom to stand or rest, they will fail the test). 10-minute rest period. Perform 50 push-ups within 2 minutes (Upper arms must parallel deck at dip and arms locked out at the top of the rep). 2-minute rest period. Perform 50 sit-ups within 2 minutes (Bent knees. Candidates hands must stay on the collarbone and the elbows must touch the knees). 2-minute rest period. Perform 6 pull-ups within 2 minutes (no kipping or swinging is allowed and the chin must clear the top of the bar on each repetition). 10-minute rest period. Run 1.5 miles (2.414 km) within 12 minutes 30 seconds. Note: The times and quantities listed are for passing the screening test only. Each candidate's scores are submitted and the candidates with the top scores along with ASVAB exam scores will be selected and given a navy diver contract. Passing the physical fitness test is necessary but by no means guarantees the candidate a contract. Health impact A study published in 2011 by the Navy Experimental Diving Unit reviewed the long-term health impact on the U.S. Navy diving population. The divers surveyed participated as divers for an average of 18 years out of their average 24 active duty years. Sixty percent of the divers surveyed were receiving disability compensation. One in seven of the divers had experienced neurologic symptoms of decompression sickness, with 41% of the divers experiencing one or more of the nine diving injuries surveyed. Seven percent of the surveyed divers had undergone a joint replacement. Eighty-six percent of the divers rated their health as "Excellent, Very Good, or Good". When compared to the general population, the divers showed better mental health but poorer physical health. Ratings and enlisted designators The navy diver rating was announced in Naval Administration Message 003/06 and consists of sailors with the following NECs: NEC 5341 — master diver NEC 5342 — first class diver NEC