ABSTRACT
The most reported strength index of the muscles of the knee has been the concentric (CC) hamstring-quadriceps ratio. It has been reported that the ratio of absolute knee extension (KE) and flexion (KE) muscle force should exceed 0.66 (Aagaard et al., 1998). Another popular ratio is derived from the eccentric (ECC) mode (i.e., KEECC/KFECC). During knee extension, the quadriceps contract concentrically (KECC) and the hamstrings contract eccentrically (KFECC). Conversely, the hamstrings contract concentrically (KFCC) and the quadriceps eccentrically (KEECC) during the knee flexion. To accurately detect muscle imbalance about the knee joint, the hamstrings-quadriceps ratio can also be described as a KEECC/KECC ratio representing knee extension, or KFCC/KFECC representing knee flexion. The simplicity of ratios makes them popular amongst researchers for ‘normalizing’ measurements of one variable with respect to another variable. Nevertheless, ratios are reliant on the assumption that the scaling exponent is a value of one in all datasets. One approach to deriving this exponent is to quantify the slope of the regression between logarithmically-transformed numerator and denominator in the ratio (Atkinson and Batterham, 2012). Differences between local and international adolescent roller hockey players in terms of the above mentioned ratios were noted in a previous report (Coelho-e-Silva et al., 2012) and this study was designed to examine the application of more accurate allometric based indices of KE and KF muscle actions as alternatives to traditional ratios in adolescent hockey players.
