ECSS Paris 2023: CP-PN09
INTRODUCTION: Previous studies have investigated the effect of short-term sprint interval training (SIT) on skeletal muscle lactate transporters (i.e., monocarboxylate transporter 1 [MCT1] and 4 [MCT4]). The studies lasted 4 to 6 weeks, and their findings were controversial. Cell-culture experiments indicate that lactate accumulation stimulates MCT1 and lactate receptor (i.e., G protein-coupled receptor 81 [GPR81]) protein expression. Besides, repeated myocardial ischaemia in rodents is accompanied by increased expression of MCT1 after 15 min reperfusion. No study has determined whether repeated periods of post-exercise ischaemia applied at the end of SIT may enhance MCT1 and MCT4 protein expression as adaptation mechanisms. In addition, only one study has studied GPR81 expression in human skeletal and reported no significant changes after resistance exercise or lactate infusion. However, the effect of SIT and ischaemia on GPR81 protein expression in human skeletal muscle remains unknown. METHODS: Thirteen physically active subjects (6M, 7F) performed a SIT programme (4-6 × 30-s isokinetic sprints with 4-min recovery periods, 3 d/w for 2 weeks). The circulation of one leg was immediately occluded (300 mmHg) after each sprint for 30-50 s, followed by unloaded pedalling without occlusion. Pre- and post-training (PRET and POSTT), each participant carried out a maximal incremental exercise test (IET), followed by a 90-min rest period, and a supramaximal exercise test (SET) (i.e., 6 × supramaximal bouts at 120% of VO2 max to exhaustion followed by 20-s recovery periods with occlusion of the two legs). Vastus lateralis muscle biopsies were obtained at rest, 90 min after IET (post-IET), and after SET (post-SET). MCTs and GPR81 protein expressions were determined by western blot in muscle biopsies. Analysis of variance and partial eta squared were used to carry out analyses. RESULTS: No significant changes in any of the analysed proteins were observed in MCTs and GPR81 with acute exercise neither before training (p > .050) nor after training in the leg trained without ischaemia. Similar results were observed in the leg trained with ischaemia (p > .050). SIT did not significantly modify the resting expression levels of MCTs or GPR81 in the leg trained with free circulation nor in the leg trained with ischaemia (p > .050). CONCLUSION: MCT1 and MCT4 protein expression in the sarcolemma may increase by 2-fold with 15 × 1 min knee extension exercise performed 4 d/w for 7-8 weeks. Our study shows that with a shorter duration training programme, despite a much higher exercise intensity and adding post-exercise ischaemia to stimulate lactate accumulation further, neither MCT1 nor MCT4 significantly increase. These findings may explain why peak lactate accumulation after short-term SIT does not increase in humans. As a novelty, we have shown that GPR81 protein expression does not seem responsive to short-term SIT in humans in human skeletal muscle. GRANT: PID2021-125354OB-C21/C22.
Read CV Agustin Manresa-RocamoraECSS Paris 2023: CP-PN09
INTRODUCTION: This study aimed to assess how altitude training impacts force-velocity-power (F-V-P) profiling and Wingate test in elite badminton players in reference to intra- and inter-individual gender-based variability. METHODS: Fourteen players (6 females, 8 males) from the French national badminton doubles team performed a 3-week “living high-training high” camp in natural altitude (2320 m). F-V-P profile and Wingate test were assessed Pre- and Post-intervention. RESULTS: No significant interaction nor time (Pre- vs. Post-) effect was observed for any of the variables (all p > 0.05). However, a significant gender effect (p < 0.05) was observed for maximal theoretical velocity and relative maximal theoretical power (Pmaxrel) for F-V-P profile and for peak and mean power outputs (both p < 0.001) for Wingate test. Pre-to-Post changes did not significantly differ between genders, except for Pmaxrel (p < 0.05) in favor of female athletes. Hedge’s g effect sizes (male minus female) revealed moderate and large effects for F-V-P profiling-derived variables. CONCLUSION: Mean conventional statistics did not reveal a significant effect of altitude training, mainly due to high intra- and inter-variability across F-V-P profiled-derived variables and Wingate performance. Substantial gender-based differences contributed to this variability, emphasizing the importance of an individualized approach to enhance participant responsiveness to altitude training.
Read CV Camille PrecartECSS Paris 2023: CP-PN09
INTRODUCTION: Participating in multiple high-intensity races in a short period can accumulate fatigue, negatively impacting subsequent performance. (1). Recognizing this, it is crucial to promptly employ fatigue recovery techniques, ensuring athletes can recover and maintain proper conditioning during rest periods whenever possible. Hyperbaric oxygen (HBO2) has been proposed to inhibit the progression of muscle fatigue and promote recovery (2). However, research on the effectiveness of HBO2 interventions during rest periods on subsequent exercise performance in competitive events with multiple races per day is still limited. Hence, this study aims to ascertain the effects of inter-exercise HBO2 exposure on subsequent anaerobic exercise performance and explore its potential to enhance athletes competitive performance. METHODS: Eight athletes performed the Wingate Test (WAnT,30s) on a bicycle ergometer twice with a 60-minute break in between. Participants also underwent two trials under different rest conditions: normobaric normoxia (NN) at 1.0 ATA with 20.93% oxygen, and hyperbaric hyperoxia (HH) at 1.3 ATA with 100% oxygen. The Wingate Test assessed both mean power and maximal power. Blood lactate concentration (BLa) and percutaneous oxygen saturation (SpO2) were measured 40 seconds before and after exercise, as well as at 3 minutes, 5 minutes, and every 10 minutes during the rest periods. Heart rate (HR) was continuously monitored from the beginning of the experiment using a heart rate monitor. The Rating of Perceived Exertion (RPE) was recorded using the Borg scale through interviews after completing the WAnT. All experimental data are presented as mean ± standard deviation. Corresponding T-tests were utilized to compare exerted power, and BLa and HR were analyzed using two-way ANOVA (condition x time). The significance level for all statistical analyses was set at less than 0.05. RESULTS: In the NN condition, the mean anoxic power after exposure was significantly reduced compared to pre-exposure (p<0.05). In contrast, in the HH condition, pre- and post-exposure values were nearly identical (p>0.05). However, there was no significant difference in maximum power between pre- and post-exposure in both conditions (p>0.05). Moreover, the HH condition exhibited significantly lower BLa and higher SpO2 after the WAnT compared to the NN condition (p<0.05). However, resting HR and post-exercise RPE showed no significant differences between the HH and NN conditions (p>0.05). CONCLUSION: For athletes who participate in multiple high-intensity races per day, our results suggest that HBO2 intervention between exercises may inhibit the accumulation of BLa and have a positive effect on physiological parameters related to oxygen saturation. These findings increase the likelihood that exposure to HBO2 during the rest period between repetitive, high-intensity exercises may contribute to promoting post-exercise recovery and maintaining subsequent exercise performance.
Read CV XIAOYUE HUECSS Paris 2023: CP-PN09