Acute Biomechanical and Physiological Responses with Concurrent Aerobic and Anaerobic Swimming Training

This study aimed to compare stroke rate (SR), stroke length (SL), and stroke index (SI) during aerobic-dominated training sets applied at speed corresponding to lactate threshold (LT) or to maximum aerobic speed (MAS) and following repeated sprints (SPR). Twelve male swimmers performed four sessions in a randomized order: (i) LT, (ii) SPR-LT, (iii) MAS, and (iv) SPR-MAS. Set LT consisted of 8 × 200 m at a speed corresponding to the lactate threshold (30 s recovery). Set MAS included 8 × 100 m at the maximal aerobic speed (30 s recovery). Set SPR included 8 × 25 m at maximal intensity (2 min recovery). Blood lactate (BL), SR, SL, SI, and rate of perceived exertion (RPE) were measured. SR, SL, and SI did not differ between LT and SPR-LT sessions (p > 0.05). In the SPR-MAS session, SR was higher and SL was lower compared to the MAS session (p < 0.05), while SI did not differ between the sessions (p > 0.05). BL at the start of LT and MAS and RPE at the end of sets were higher in the SPR-LT and SPR-MAS sessions (p < 0.05). BL and RPE were correlated with SR in 8 × 200 m during the SPR-LT session (p < 0.05). Repeated sprints may change the biomechanical and physiological response during a subsequent training set performed at MAS while preserving technical efficiency.