Throwing instruction has received considerable attention in the developmental literature (Ehl, Roberton, & Langendorfer, 2005; Pulito-Runion, Roberton, & Langendorfer, 2003). However, most research has used a ‘black box' (pre-to-post differences) approach (Dunkin & Biddle, 1974) within the research design. It is unclear how specific throwing behaviors emerge and the coupling of different body components in the development of the overarm throw. This study was part of a larger study that examined the influence of a throwing intervention on the throwing patterns of 117 preschool children. This piece, investigated the relationship between skill level, the number of practice trials, and gender on the emergence of throwing patterns of preschool-aged children. Sixteen preschoolers (M = 53.75 mo., SD = 9.67 mo.) were purposively selected to represent high and low skilled boys and girls. All children received 7, 10-min throwing sessions across 7 weeks. Each session was videotaped and the number of throwing trials per session was recorded for each participant. At the end of each session, five trials of overarm throws were performed and coded using Roberton and Halverson's (1984) developmental sequence of the overarm throw. Individual graphs were plotted for each child representing the modal developmental status for the step, trunk, humerus, and forearm components for each day of instruction along with the number of throwing trials for that day. Charts were visually inspected to observe the developmental trajectories of the body components and the coupling of one component to another. These data suggested a “coupling effect” between the step and trunk components, a contralateral step is required before a child can “rotate the trunk” on their legs. A secondary “coupling effect” was found between the trunk and humerus components. A stable pattern of block rotation was present before participants begin to experiment with the positioning of the humerus. In regards to the developmental trajectories, all low skill performers demonstrated a throwing profile of T1H1F1 (8) at the start of the intervention and ended with a T2H1F1 (1), T2H2F1 (1), or T2H2F2 (6). The high skilled performers began the intervention with more proficient throwing behaviors that consisted of a T2H1F1 (2), T2H2F1 (4) or T2H2F2 (2) and finished the intervention demonstrating a T2H2F2 (2) or T2H3F2 (6). The findings demonstrated the “coupling” of overarm throwing components along with common developmental pathways in young children throwing behavior. The results serve as a guide for task sequencing for overarm throwing instruction.Keyword(s): early childhood, motor skills, physical education PK-12