Alternative Approaches to Assessing the Anaerobic-Aerobic Power Ratio; Age Related Changes from Childhood to Early Adulthood

Abstract

<p> The anaerobic-to-aerobic power ratio is a useful tool to evaluate the strengths and weaknesses of both the aerobic and anaerobic energy systems. The traditional method of calculation has shown this ratio to increase with age in children and to plateau by late adolescence or early adulthood. However, by using the traditional approach, the aerobic component of the ratio is likely highly influenced by anaerobic sources and therefore, may not demonstrate the true proportional changes observed in the respective physiological capacities comprising this ratio with age through childhood and adolescence. The purpose of this study was to examine the age-related development of the power ratio using two new approaches. The lactate threshold (LT) and ventilatory anaerobic threshold (VAT) were identified in 31 competitive male hockey players ranging from 10 to 21 years of age and compared across three discrete age groups. Peak mechanical anaerobic power was obtained from a Wingate test (WAnT) and incorporated into the numerator of the power ratio, while peak mechanical aerobic power was obtained from a modified McMaster all-out progressive test and included into the denominator of the ratio. Mechanical power at the LT and VAT were also identified and integrated into the denominator of the power ratio and results compared to the traditional approach to identify similarities or differences in developmental trends with age. Furthermore, the reliability of the traditional, LT and VAT approaches was examined with retests of six subjects using intra-class correlation analysis and Method Error analysis. When power ratio approaches were compared among discrete age groups, significant differences (P≤0.05) were found between the youngest and oldest age groups for each of the three approaches. Notwithstanding the trend for progressive increases with advancing age group for all approaches, significant correlations with age were only found for the traditional approach (r=0.36). Finally, the VAT approach was the most reliable (r=0.95; ME=0.13) while the LT and traditional approaches demonstrated strong but non-significant test-retest correlations. Results of this study suggest that the LT and VAT approaches may theoretically be more accurate methods of measuring the power ratio than the traditional approach, as there is likely less anaerobic contribution to the denominator of the ratio. Each of the new approaches demonstrates expected age-related trends, and notwithstanding methodological and sample limitations, the VAT in particular, appears to be a more reliable and accurate means of assessing the power ratio compared to the traditional or LT approach.</p>