“Selecting the right tool for the job” a narrative overview of experimental methods used to measure or estimate active and passive drag in competitive swimming

Free-swimming performance depends strongly on the ability to minimise resistive drag. Therefore, estimating resistive drag (passive or active) may be important to understand how free-swimming performance can be improved. The purpose of this narrative overview was to describe and discuss experimental methods of measuring or estimating active and passive drag relevant to competitive swimming. Studies were identified using a mixed-model approach comprising a search of SCOPUS and Web of Science data bases, follow-up of relevant studies cited in manuscripts from the primary search, and additional studies identified by the co-authors based on their niche areas of fluid dynamics expertise. The utility and limitations of the methods of measuring active and passive drag were critically discussed with reference to primary research domains in this field, ‘swimmer morphology’ and ‘technique analysis’. This review and subsequent discussions provide implications for researchers when selecting an appropriate method to measure resistive forces (active or passive) relevant to improving performance in free-swimming.