To the Editor.— In the study "Physical Fitness in US and Austrian Military Personnel" by Cooper ( 215 :931, 1971), the author mentions a lack of explanation for the difference in physical fitness among the incoming recruits of the US Air Force and the Austrian Army. The incoming recruits of the Austrian Army fared much better in the performance of the applied 12-minute field test. Fifteen years ago, Dr. Hans Kraus performed extensive physical fitness studies among American highschool students and Austrian children of corresponding age. 1-3 The so-called Kraus-Weber test, which tests for flexibility and strength of the trunk muscles, was applied. The results of the studies showed a much higher failure rate among American high-school students as compared with Austrian students. The Kraus-Weber test was criticized as being too simplified to serve as a screening test for physical fitness. In the light of Cooper's studies, it appears that the