The reliability and validity of the T-test as a measure of leg power, leg speed, and agility were examined. A total of 304 college-aged men (n = 152) and women (n = 152), selected from varying levels of sport participation, performed 4 tests of sport skill ability:​ (a) 40-yd dash (leg speed), (b) countermovement vertical jump (leg power), (c) hexagon test (agility), and (d) T-test. For both men and women, significant differences (p < 0.05) in mean scores were found among groups for the T-test. The intraclass reliability of the T-test was 0.98 across 3 trials. For men, the Pearson product moment correlations between the T-test and the 40-yd dash, vertical jump, and hexagon test were r = 0.53, r = 20.49, and r = 0.42, respectively (p < 0.05). For women, the corresponding correlations were r = 0.73, r = 20.55, and r = 0.48 (p < 0.05). Regression analyses showed that for men 48% of the variability and for women 62% of the variability of the T-test scores can be predicted from measures of leg power, leg speed, and agility (p < 0.05). Computing partial correlations assessed the criterion validity of the T-test as a measure of agility, leg power, and leg speed. The T-test appears to be highly reliable and measures a combination of components, including leg speed, leg power, and agility, and may be used to differentiate between those of low and high levels of sports participation.