Simulated 200 Mt Swimming Event Imposes High Blood Lactate Levels In The Middle Section

BACKGROUND: Swimming events like the 200-m freestyle race impose high blood lactate (BLa) levels (Vescovi et al., 2011). In this event, pace times remain stable in the middle section and the best swimmers are slightly faster in the final lap (Robertson et al., 2009). We recently proposed applying interval training at pace and high BLa values ​​in steady state to stimulate these needs (Mazza et al., 2024). However, it is unknown whether these paces generate BLa steady state values during 200-m freestyle simulated event. PURPOSE: To analyze the behavior of the BLa during a simulated 200-m freestyle event. METHODS: Ten national-level swimmers (18.10 ± 2.73-y; 66.01 ± 8.41-kg; 174.63 ± 7.96-cm) with 5.80 ± 1.75-y of experience and a current personal best of 119.92 ± 4.65-sec in 200-m freestyle performed two interventions in a 25-m pool: [a] an all-out 200-m freestyle bout (B1) measuring the pace at 0 to 50-, 50- to 100-, 100- to 150-, and 150 to 200-m, and BLa at 60 and 180-sec post bout, considering the highest value; and [b] four days later, another 200-m freestyle bout (B2) reproducing the pace of each 50-m section of B1 (broken set), assessing BLa as fast as possible at 50-, 100-, and 150-m and BLa post bout as in B1. One- and two-way ANOVA, T tests, and effect sizes (η2p and d) with p < 0.05 were applied. RESULTS: There were no differences between pace bouts (F1 = 1.64, p = 0.205, η2p = 0.02). The 0- to 50-m pace was faster than 50- to 100-, 100- to 150-, and 150- to 200-m in both B1 (27.37 ± 0.94, 30.59 ± 1.37, 31.47 ± 1.81, and 31.30 ± 1.59-sec, respectively; p < 0.001, d < -2.11) and B2 (26.90 ± 1.13, 30.31 ± 1.70, 30.83 ± 1.68, and 30.94 ± 1.72-sec, respectively; p < 0.001, d < -2.24). Peak BLa was higher in B1 compared to B2 (13.25 ± 2.20 vs. 9.59 ± 1.93 mmol/L, respectively, p = 0.003, d = 1.24). BLa increased at each 50-m time point during B2 (3.78 ± 1.69, 7.52 ± 1.65, and 8.88 ± 1.69 mmol/L, p < 0.01). There were no differences in BLa extraction times between 50-, 100-, 150-m (p = 0.950, η2p = 0.01) and the overall average was 10.93 ± 1.84-sec. CONCLUSIONS: Despite the differences, the middle section of a simulated 200-m freestyle swimming event imposes high BLa levels at near metabolic steady state (Δ <1.5 mmol/L), which is likely to occur in a race given the similar performance time. The lower BLa peak is possibly due to broken rest, although the mechanisms of this should be studied.