Maximal athletic performance can be limited by various factors, including restricted respiratory function. These limitations can be mitigated through targeted respiratory muscle training, as supported by numerous studies. However, the full potential of respiratory training in competitive finswimming has not been fully investigated. This case study aims to evaluate the effects of eight-week respiratory muscle training (RMT) on performance variability during the underwater phases of a 200 m bi-fins race simulation in an elite finswimmer (current world record holder and multiple world championship medalist). Performance variability was assessed based on pre-test, inter-test, and post-test data. Each measurement included pulmonary function and swim performance evaluations. In this study, underwater performance parameters, such as distance, time, velocity, and number of kicks, were assessed using video analysis synchronized with race timing and evaluated using the Dartfish software. The swimmer followed a 28-day training program with an Airofit PRO™ respiratory trainer between tests, with daily sessions targeting both inspiratory and expiratory muscles. The training involved 6–10 min of targeted exercises per day. Significant improvements were observed in Wilcoxon’s paired-sample test between the pre-test and post-test results in terms of underwater distance (p = 0.012; d = 1.26), underwater time (p = 0.012; d = 1.26), and number of underwater kicks (p = 0.043; d = 1.01), resulting in a 14.23% longer underwater distance, 14.08% longer underwater time, and 14.94% increase in underwater kicks. Despite the increased distance and time, underwater velocity remained stable, indicating improved underwater performance efficiency. Despite some improvements, it is not possible to conclude that respiratory muscle training (RMT) can contribute to improved finswimming performance during the underwater phases of a 200 m bi-fins race simulation in this particular athlete’s case. Further research with a larger sample size is necessary to fully understand the impact of RMT on finswimming performance.

Maximal athletic performance can be limited by various factors, including restricted respiratory function. These limitations can be mitigated through targeted respiratory muscle training, as supported by numerous studies. However, the full potential of respiratory training in competitive finswimming has not been fully investigated. This case study aims to evaluate performance variability during underwater phases in an elite Bi-Fins swimmer (current world record holder and multiple world championship medallist) over a 200m race simulation after an eight-week respiratory training using Airofit PRO™. Performance variability was assessed based on pre-test, inter-test, and post-test data. Each measurement included pulmonary function, body composition, and swim performance evaluations. The swimmer followed a 28-day training program with the AiroFit PRO™ respiratory trainer between tests. Significant improvements were observed in Wilcoxon paired-sample test between the pre-test and post-test in underwater distance (p=0.012; d=1.26), underwater time (p=0.012; d=1.26), and number of underwater kicks (p=0.043; d=1.01), resulting in a 14.23% longer underwater distance, 14.08% longer underwater time, and 14.94% increase in underwater kicks. Despite increased distance and time, underwater velocity remained stable, indicating improved underwater performance efficiency. The results suggest that the AiroFit PRO™ respiratory trainer has practical applications in finswimming training programs.

This study examined the acute effects of sodium bicarbonate (NaHCO₃) supplementation on performance, stroke mechanics, as well as physiological and perceptual responses during a simulated 200-m Bi-Fins race. Nineteen national-level athletes (10 females, 9 males) completed a randomized, double-blind, placebo-controlled crossover trial under three different conditions: control, placebo, and NaHCO₃ supplementation (300 mg·kg⁻¹ body mass). Performance and biomechanical variables (split times, stroke rate, stroke length, stroke index) were obtained from video analysis, while blood samples were collected pre- and post-test to assess acid-base status and lactate. Ratings of perceived exertion (RPEs) and muscle soreness (VAS) were also recorded. NaHCO₃ supplementation induced systemic alkalosis, with higher pre-test HCO₃⁻ (30.1 ± 1.8 mmol·L⁻¹), pH (7.484), as well as ABE (+6.5 mmol·L⁻¹), with these values remaining elevated post-test compared to control and placebo conditions (all p < 0.001). Early splits (25 and 50 m) were slower after NaHCO₃ supplementation (p < 0.05). Post-test blood lactate was slightly higher following the placebo supplementation (14.3 vs. 13.4 mmol·L⁻¹, padj= 0.030), although the absolute difference (<1 mmol·L⁻¹) was physiologically small. RPEs were reduced after NaHCO₃ versus placebo supplementation (padj = 0.002; large effect), while no significant differences were observed in VAS scores. These findings demonstrate that although NaHCO₃ supplementation effectively induced alkalosis and lowered perceived exertion, it did not improve overall performance, with only very small changes in biomechanical variables during certain race sections. From a practical perspective, the attenuation of acidosis and reduced exertion may support faster recovery and performance stabilization in repeated-race formats (e.g., heats and finals).