Abdominal muscle strength and endurance are widely assessed by means of a timed 1‐minute full sit‐up test, despite the more accepted use of half sit‐ups as a muscular strength and endurance exercise. In the present study, the validity and reliability of a 1‐minute half sit‐up protocol was investigated. A total of 142 different subjects participated in one of four studies designed to assess test‐retest reliability, interapparatus reliability, intertester reliability, and validity. Findings included very high test‐retest reliability (r = 0.98), moderately high interapparatus reliability (r = 0.71), and high intertester reliability (r = 0.76). The correlation of the half sit‐up test with the full sit‐up test of the National YMCA was 0.67 and the correlation with isometric abdominal strength was 0.38. The proposed half sit‐up test was found to be reliable and is proposed as an alternative method of evaluating abdominal strength and endurance.