Fatigability after 6 Weeks of Concurrent Dryland and Sprint Swimming Training

Abstract This study examined whether the acute effects of dryland muscular endurance training on subsequent strength and swimming responses differed before (T1) and after (T2) 6 weeks of muscular endurance and sprint interval training. Sixteen male and female swimmers (16.3±3.2 y) were ranked according to their 100-m performance and divided into groups trained with muscular endurance and sprint interval training (n=8) and sprint interval training (n=8). At T1 and T2, both performed a 1-RM evaluation and completed muscular endurance and swimming and swimming conditions in counterbalanced order. At T1 and T2 between conditions %Δ of swimming performance, tethered force, hand grip, isometric shoulder strength, blood lactate, stroke rate, stroke length, stroke index, and arm-stroke efficiency were calculated: %Δ=([muscular endurance+swimming−swimming]/swimming)x100. The 1-RM and external load were increased in groups trained with muscular endurance and sprint interval training only at T2. No differences (p>0.05) between groups were found in swimming performance, tethered force, blood lactate, stroke rate, stroke length, stroke index, and arm-stroke efficiency at T1 and T2. Isometric shoulder strength in group trained with muscular endurance and sprint interval training decreased after swimming at T1 and increased at T2 (−8.1±15.8 vs. 0.68±12.68%), whereas the opposite occurred in group trained with sprint interval training (4.22±12.42 vs.−1.64±12.29%, interaction, p=0.02). Six weeks of concurrent muscular endurance and sprint interval training improved strength and maintained swimming performance despite increased external loading during the concurrent training session.