The purpose of this study was to examine the effects of shoe wear on ground reaction forces (GRF) produced in a grapevine maneuver (tempo=154 bpm). GRF for both shod and barefoot conditions were collected at three different intervals of shoe wear time (0, 40, & 80 hours). Seventeen women who practiced aerobic dance regularly volunteered for participation in the study (age=26.4, SD=6.4 yrs; height = 165.8, SD=6.9 cm; weight = 62.4, SD=4.0 kg). Five support phase trials were collected on the final step of the third consecutive grapevine using an AMTI force platform mounted flush with the surface. Selected vertical, anteroposterior and mediolateral GRF variables were analyzed and compared across both the trial and shod/barefoot conditions using a multivariate analysis of variance. There were significant differences across the wear intervals for several ground reaction variables (p£0.05). There was a significant trial effect in the vertical direction for the magnitude of the initial loading force, impulse to the initial loading force, the subsequent minimum force, and time to the second peak force. A trend toward increased force, time and impulse characteristics were observed in the 40 to 80 wear interval and no changes were observed between the 0 and 40 hours of wear. There were no significant trial effects for the mediolateral forces or the anteroposterior forces. Differences between the barefoot and the shod conditions were apparent for temporal parameters with shoe conditions achieving maximum contact, maximum propelling forces, and maximum anterior forces later than the barefoot conditions. These results suggest there may be an effect of shoe wear on the performance of an aerobic skill and further study is needed to sort out the actual influence of shoe wear by continuing to examine characteristics throughout the life of the shoe. Keyword(s): exercise/fitness, physical activity