Aerobic and Anaerobic Metabolism During Monofin Swimming in Trained Breath-Hold Divers.

This study aimed to examine the difference in blood lactate and oxygen saturation between monofin swimming with respiration and with breath-hold diving. The second aim was to investigate the difference between elite and intermediate breath hold-divers. This study included 15 freediving athletes (five females). Their chronological age was 25.9 ± 2.9 years, body mass 75.5 ± 11.9 kg, and height 180.2 ± 8.9 cm. The sample of variables included anthropometric indices, blood lactate, and oxygen saturation. The participants were measured during 100 m monofin horizontal swimming with respiration and breath-hold diving. Descriptive and inferential statistics were measured. The Kolmogorov-Smirnov (K-S) test was used to determine the normality of distribution. To determine the differences between the groups of participants, the -test was used to determine the differences in anthropometric indices. Furthermore, to observe the differences between repeated measures, ANOVA with Fischer LSD test was used. Following that, the two-factor ANOVA analysis group (respiration/apnea) and group (intermediate/elite level)) was performed to determine the possible differences between groups in both conditions. Also, Cohen's effect size was calculated to quantify the differences among the measurements. The results show that the divers perceive significantly smaller levels of lactates during dives with respiration (intermediate, 2.44 ± 0.64 mmol/L; elite, 2.23 ± 0.34 mmol/L) than during apnea (intermediate, 6.06 ± 2.00 mmol/L; elite, 4.10 ± 0.66 mmol/L). Furthermore, intermediate freedivers tend to perceive significantly higher values. To conclude, it can be noted that apnea monofin diving elicits significantly higher lactate production in comparison with distance-matched swimming. Such findings imply the anaerobic nature of breath-holding diving. Apart from that, elite divers tend to show a lower accumulation of lactate. Such findings imply that elite-level divers can endure prolonged apneas with lower anaerobic metabolism use.