Dual task situations are very common in daily life. The cost of dual task condition has been widely used by researchers and clinicians to categorize individuals, as indicators of decline of functional capacities in older or persons with cognitive or motor disabilities. Moreover, the comparison between performances in single and dual tasks situations permits the calculation of the effect of dual task, which can be beneficial or detrimental for cognitive or motor tasks. Based on our results of a previous interventional study, we defined a dual task model analysis from the evolution of the effect of dual task after 12 weeks of exergaming in older adults. This approach led us to the proposal of a representation of dual task progress (DTP). This theorical model is sensitive to reliability of DT outcomes measurement and needs to be validate in the future.