The aim of this work is to examine the influence of performance rate in the test of curls in adolescents. We studied 67 secondary students (26 men and 41 women) who randomly did two curl tests to measure abdominal force-resistance: a) test of maximum rate of repetitions in 30 seconds, b) test of slow stable rate of 25 repetitions a minute for a maximum of 3 minutes. Results: We did not see any significant differences between both sexes in the number of curls at a stable rate. On the other hand, the men did more curls at a rapid rate in 30 seconds than the women. The lineal relationship between both test was very low (rpearson = 0,31 , p < 0.05). Kendall’s concordance test showed very significant difference; (p 0.001) between the order of the subject according to the result obtained in one test and that obtained in the other. Conclusions: 1) the test of curls at a stable slow rate of 25 repetitions per minute show different physical characteristics from the test that tries to obtain the maximum number of curls in 30 seconds. 2) in the case of applying the rapid rate test in 30 seconds in youngsters the comparative evaluation between the subjects (percentile) would require reference values different for men and for women. On the other hand we did not find this necessity in the stable slow rate test. 3) weight height and the body mass index of the subjects had no significant relationship with the result obtained in the two tests. 4) the result obtained in one of the tests by one single person does not permit us to predict what could be obtained in the other.