The purpose of this study was to compare the acute effects on youth fitness of 3 different warm-up protocols utilizing static stretching or dynamic exercise performance. Sixty children (mean age 11.3 +/- 0.7 years) performed 3 different warm-up routines in random order on nonconsecutive days. The warm-up protocols consisted of 5 minutes of walking and 5 minutes of static stretching (SS), 10 minutes of dynamic exercise (DY), or 10 minutes of dynamic exercise plus 3 drop jumps from 15-cm boxes (DYJ). Following each warm-up session, subjects were tested on the vertical jump, long jump, shuttle run, and v-sit flexibility. Analysis of the data revealed that vertical-jump and shuttle-run performance declined significantly following SS as compared to DY and DYJ, and long-jump performance was significantly reduced following SS as compared to DYJ (p < 0.05). There were no significant differences in flexibility following the 3 warm-up treatments. The results of this study suggest that it may be desirable for children to perform moderate- to high-intensity dynamic exercises prior to the performance of activities that require a high power output.