Can experienced runners accurately estimate performance capabilities to derive the parameters of the critical velocity model ?

This study examined the accuracy of estimated performance times to define the parameters of the critical velocity (CV) model. Twelve subjects provided an estimated time to complete (ETcom) maximal-effort runs at four different distances (400m, 800m, 1600m, and 3200m). The CV and anaerobic running capacity (ARC) were derived from the total distance (TD) versus ETcom relationship. The equation: predicted time to completion ([PTcom] = ARC/(velocity-CV)) was used to determine the PTcom for runs at three different distances (200m, 600m, and 1000m). The PTcom was validated against the actual time to complete (ATcom) runs at the same three distances. The TD versus ETcom relationship was highly linear and indicated a close relationship between running distance and time. The PTcom overestimated the ATcom at 200m, but there were no significant differences between the PTcom and ATcom at 600m and 1000m. There were, however, no significant relationships between PTcom and ATcom at any of the three distances. These findings indicated that the CV model could be applied to estimated running times to derive the CV and ARC parameters, but the parameters of the test could not be used to accurately estimate individual performance times above CV using the equation PTcom = ARC / (V-CV). 1. Introduction The critical velocity (CV) model was developed [1] as the treadmill analog to the critical power (CP) model for cycle ergometry. Running velocity and the time to exhaustion (Tlim) conformed to the same hyperbolic relationship that had previously been shown for power output versus Tlim during cycle ergometry [1]. The CV model provides estimates of two separate parameters, CV and anaerobic running capacity (ARC), that are defined as the slope and the y-intercept of the total distance (TD) and Tlim relationship, respectively. It has been suggested [2] that CV represents the highest sustainable (at least 30 min) running velocity, where metabolic responses (VO2 and blood lactate) reach steady state values. The ARC parameter reflects the total amount of work that can be performed using only the energy stores within the working muscle (phosphocreatine, adenosine triphosphate, glycogen, and the oxygen bound to myoglobin [3, 4] , and is limited by the accumulation of metabolic byproducts and ions [5]. Thus, the CV model provides estimates of two separate parameters, CV and ARC, which reflect the aerobic and anaerobic capabilities, respectively. One potential application of the CV model is the prediction of performance for intensities above the CV [3]. Currently, there are conflicting data regarding the ability of the CV model to accurately predict performances. For example, Pepper et al. [6] indicated the CV model accurately predicted the time to exhaustion at 115% of CV, but it was over predicted at 100 and 130%. During cycle ergometry, however, the time to exhaustion was accurately predicted at all power outputs above CP [7]. Thus, the results of previous studies [6, 7] indicated there is conflicting evidence regarding the ability of the CP/CV model to provide an accurate estimate of the subjects' performance capabilities at power loadings greater than CP or CV. Typically, the CV test parameters are determined from multiple, constant power output or velocity work bouts, performed to exhaustion. The total distance (TD) is then plotted against the time to exhaustion (Tlim) to derive CV and ARC.