Validation of a Backswing Developmental Sequence for the Overarm Throw for Force

Abstract

Background: Roberton’s movement components are used to assess fundamental motor skills as segmental developmental sequences. In 1991, Haywood, Williams and VanSant determined that original developmental sequences proposed for the backswing levels of the overarm throw did not encompass all ages. Their study of older throwers identified two new qualitatively different levels, with half the participants categorized at two new levels. This investigation extended the initial validation across a wider age range. Method: Two hundred and twenty-eight primary, high school, university students, and adults were instructed to make five throws for maximum force using their dominant hand. Throws were recorded with side and rear cameras synchronized for analysis. Prelongitudinal screening was used to analyze the Haywood et al. revisions of the Langendorfer developmental sequence. Results: Five of the six levels of Haywood’s sequence were suitable for assessing throwers 8 years of age through to adulthood. More study is needed of one less advanced pattern. Lower level throws corresponded to lower velocities; higher level throws were faster, suggesting the sequence was properly ordered. More males than females were classified at higher levels, demonstrating typical gender differences. Discussion: The categories hypothesized for the backswing action of the overarm throw were valid descriptors of differences observed across ages, from childhood to adulthood. Additional study of Levels 3 and 4 is warranted to clarify their order.