When identifying motor difficulties such as DCD, there is dissension as to what cut points should be used in research and intervention. These cut points are generally based on motor performance test scores and range from the 5th to the 15th percentile. The adoption of the lower point should be challenged because many children, who also have movement related psychosocial difficulties and low fitness, may not be identified. Two limitations arise from using the 5th percentile as a cut-score: a) given the multi-causal nature of DCD, research using a low cut-off might limit what we can ever know; and b) the research findings will have limited generalisability to future practice. The controversy surrounding cut points, and the heterogeneous nature of DCD, highlight the need for more data-based work to broaden our understanding of the limitations we impose by selecting a specific cut point.
Our purpose was to identify clusters based on fitness and physical self-perceptions of adolescents with extremely low to marginal motor performance scores. We looked to see whether these clusters provided support for a motor performance cut point that was 2 SD below, 1.5 SD below, 1.25 SD below or 1 SD below the mean of the MAND Neurodevelopmental Index (McCarron, 1997). The 14-year-old participants (N = 317) completed the athletic subscale of the Self-Perception Profile for Adolescents (Harter, 1988), three questions on enjoyment and ability in physical activities, and fitness measures: BMI, upper limb strength; abdominal endurance; flexibility; and PWC170.
Rose, E., Larkin, D., Hands, B., & Parker, H. (2008). Issues in the identification of development coordination disorder. Paper presented at the 9th European Congress of Adapted Physical Activity. Turin, Italy.