**Figure 3.** Performance (predictive value of change [+] and no-change [-]) of acute heart rate (HR) and rate of perceived exertion (RPE) responses to three jump rope workouts (at 100, 120 and 140 rotations per min, rpm) to predict changes in high-intensity intermittent running performance (V_{IFT}) after the training intervention, while using different approach to determine the smallest worthwhile change (SWC): either 1) the typical error of measurement of each variable (expressed as a CV), 2) a small standardized effect based on Cohenâ€™s effect size principle (0.2 x between-athletes standard deviation, SD) or 3) the actual changes in HR and RPE response that relate to a small standardized (0.2 x between-athletes SD) change in V_{IFT}.