Variables and protocols of the tethered swimming method: a systematic review

Background The tethered swimming (TS) is an ergometer where swimming is simulated in an ecological environment, commonly used for assessing force in water. Objective This systematic review aims at a critical appraise of the literature on the biomechanical and physiological variables obtained from many protocols and tests assessing force–time curve in TS. Methods We explored the databases of PubMed, EMBASE, SPORTDiscus, Web of Science, and Academic Search Premier (PROSPERO protocol CRD42020204826), and manually searched the reference papers list. Observational studies with swimming protocols and tests were included (with any follow-up and published in the full version). The following exclusion criteria would be used, but they were not necessary, as no case met these criteria. Our search was based on the adapted Downs and Black Quality Assessment Checklist. Results In total, 55 articles were examined extensively for fitting the established inclusion criteria. Quality of the articles included ranged from 35.7 to 85.7% (65.7 ± 13.3%). Most studies addressing TS were assessed [peak = 41 and average force = 39], whereas only a very few studies referred to measures of [force impulse = 21, fatigue index = 11, force development rate = 5], and physiological variables [oxygen consumption = 10, blood lactate concentration = 8, and heart rate = 6]. The studies were carried out with durations of 10 s, 15 s, 20 s, 25 s, 30 s, 55 s, 1, 2, or 3 min, related to the duration to perform 10 and 20 complete strokes in front crawl swimming technique. Conclusion Based on the general results of this systematic review, the impulse seems to be the most reliable measure and presented linear correlation with swimming speed. In contrast, the TS physiological responses show compatibility for the aerobic response, critical force, and maximal oxygen uptake determination.