Which of the following is NOT true concerning the curl-up test? A. The curl-up only tests the endurance of the abdominal muscles, not their strength. B. Curl-ups are performed while lying on the floor with knees slightly bent. C. The fingers are supposed to slide 3.5 inches along the floor during a curl-up. D. Curl-ups are supposed to be done at a rate of about one every three seconds.