A number of familiarization trials are needed for reliable measurement, particularly for inexperienced subjects. Researchers have studied and developed familiarization protocols that vary by exercise and study population. The pace of familiarization and fatigue may be an individual-level characteristic, so a population-level protocol may not fit all subjects. In this article, the authors view this practical challenge as a statistical problem. We apply piecewise linear regression and model averaging for estimating the true performance level of a subject after familiarization and before fatigue. This statistical method does not require an experimenter to determine when a study participant is familiarized and fatigued. Simulation studies demonstrate that this statistical approach provides a more reliable measurement than the best-fit model. An online interactive applet is provided for those who are not familiar with statistical programming. Detailed instructions for the applet and case study are provided for demonstration.