When the new Army combat fitness test (ACFT) was launched, weightlifters rejoiced, as did people who hated the sit-up test. Gone were the days of push-ups, sit-ups and two-mile run. Well, not quite.

The old Army physical fitness test (PFT) of push-ups, sit-ups and a two-mile run was (and still is) a decent test of basic health and fitness. It has been used in studies to show that average to above ...