Applying Rasch to confirm the underlying construct of a new process instrument in Gymnastics

Three cohorts were observed performing a gymnastic locomotor skill – the forward roll. These groups included: children (<i>n</i>=48) aged between 6 years and 15 years; young adults (<i>n</i>= 24) aged between 18 years and 22 years; and, older adults (<i>n</i> = 45) aged between 28 years and 42 years. Qualitative analysis of visually recorded data resulted in the forward roll being categorised into three sequences, the <i>beginning</i>, <i>middle</i> and <i>end</i>. For each sequence a number of <i>indicators</i> were identified. Each <i>indicator</i> was further sub-divided into a number of <i>descriptors</i>. These <i>descriptors</i> were hierarchically ranked and using the <i>Quest</i> (ACER) statistical package a Rasch analysis was employed to determine whether the <i>descriptors</i> confirmed the underlying construct. The application of the Rasch model was confirmatory for identifying the structure of a range of quality movement performances.