Development of a mature vertical jump (VJ) is important to successful sport participation and related to the ability to absorb landing forces. Yet, many girls, even by age 10, fail to jump with a mature pattern, increasing their landing injury risks (e.g., non-contact ACL). The purpose of this study was to use video analysis to determine the effectiveness of two classroom-teaching aids on the VJ pattern of girls aged 9-11. Both aids were expected to increase shoulder hyperextension and lower extremity joint extension at take-off. Forty-seven volunteers signed an approved consent to participate. Pre-testing determined baseline VJ pattern. Markers were placed at the shoulder, elbow, hip, knee, and ankle joints. The teacher modeled the desired VJ, including verbal cues designed to elicit a mature pattern. Subjects performed 10 maximal effort VJs, resting briefly if needed. The last five jumps were videotaped with a standard video camera mounted a top a tripod, 20 ft. from the sagittal plane. Data were analyzed with Never Ending Athletic Trainer (NEAT) software. An arm swing group (ASG) was formed (i.e., subjects lacking shoulder hyperextension) along with a target group (TG) (i.e., subjects lacking lower extremity joint extension at take-off). Forty-three subjects completed post-testing. Procedures replicated the pre-test, except two teaching aids were introduced. The ASG brushed their fingertips along a vinyl-coated Swedish box, i.e., with shoulder hyperextension and shoulder flexion. The TG reached for a balloon hung within the circle of a horizontally suspended hula-hoop. ANCOVAs determined post-test differences between groups using pre-test scores as covariates, since pre-test VJ patterns varied. No significant group differences in shoulder hyperextension, and hip, knee, and ankle extension at take-off were evident. The TG (p = 0.000) increased (.0806 m) jump height while the ASG (p = .001) decreased forward displacement (.0269 m). Given no pattern differences between the teaching aid groups, a series of paired sample t-tests were used. Results indicated (p = 0.000) increases in shoulder hyperextension (19.26o) and ankle plantar flexion (4.23 o) for all subjects. There were no movement pattern distinctions among the influences of either aid, but both aids increased shoulder hyperextension during the countermovement and ankle plantar flexion at take-off. Thus, physical educators may use either aid within the gymnasium context to improve the VJ pattern of young girls. These improvements may benefit sport participation and decrease injury risk upon landing. Future studies should assess the impact of long-term practice with each aid.Keyword(s): athletics/sports, elementary education, safety/injury prevention