The measurement of resistance training (RT) is often based on adaptations of aerobic physical activity measures which may not contain the elements necessary to assess RT. The purpose of this systematic review was to examine what measures are used to assess RT and appraise their composition. Specifically, the inclusion of frequency, duration, intensity, the use of major muscle groups, reps, and sets. Search terms included "resistance training," "strength training," OR "weight training" AND "behavior" OR "participation." Studies were evaluated based on whether RT measures assessed the key components of participation. In the 92 included studies, only one of the six components of the RT recommendations was assessed on average. This was almost exclusively frequency. Many assessments of RT were adapted from aerobic measures without rigorous validity evidence. Construct validity in RT measurement may lead to improved public health recommendations, surveillance of behavior, and precision in determining effective interventions and correlates.