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 (n=48) aged between 6 years and 15 years; young adults (n= 24) aged between 18 years and 22 years; and, older adults (n = 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 beginning, middle and end. For each sequence a number of indicators were identified. Each indicator was further sub-divided into a number of descriptors. These descriptors were hierarchically ranked and using the Quest (ACER) statistical package a Rasch analysis was employed to determine whether the descriptors confirmed the underlying construct. The application of the Rasch model was confirmatory for identifying the structure of a range of quality movement performances.