Effects of Eight Interval Training Sessions in Hypoxia on Anaerobic, Aerobic, and High Intensity Work Capacity in Endurance Cyclists

Effects of various living-low and training-high modes with distinct training prescriptions on sea-level performance: A network meta-analysis

This study aimed to separately compare and rank the effect of various living-low and training-high (LLTH) modes on aerobic and anaerobic performances in athletes, focusing on training intensity, modality, and volume, through network meta-analysis. We systematically searched PubMed, Web of Science, Embase, EBSCO, and Cochrane from their inception date to June 30, 2023. Based on the hypoxic training modality and the intensity and duration of work intervals, LLTH was divided into intermittent hypoxic exposure, continuous hypoxic training, repeated sprint training in hypoxia (RSH; work interval: 5-10 s and rest interval: approximately 30 s), interval sprint training in hypoxia (ISH; work interval: 15-30 s), short-duration high-intensity interval training (s-IHT; short work interval: 1-2 min), long-duration high-intensity interval training (l-IHT; long work interval: > 5 min), and continuous and interval training under hypoxia. A meta-analysis was conducted to determine the standardized mean differences (SMDs) among the effects of various hypoxic interventions on aerobic and anaerobic performances. From 2,072 originally identified titles, 56 studies were included in the analysis. The pooled data from 53 studies showed that only l-IHT (SMDs: 0.78 [95% credible interval; CrI, 0.52-1.05]) and RSH (SMDs: 0.30 [95% CrI, 0.10-0.50]) compared with normoxic training effectively improved athletes' aerobic performance. Furthermore, the pooled data from 29 studies revealed that active intermittent hypoxic training compared with normoxic training can effectively improve anaerobic performance, with SMDs ranging from 0.97 (95% CrI, 0.12-1.81) for l-IHT to 0.32 (95% CrI, 0.05-0.59) for RSH. When adopting a program for LLTH, sufficient duration and work intensity intervals are key to achieving optimal improvements in athletes' overall performance, regardless of the potential improvement in aerobic or anaerobic performance. Nevertheless, it is essential to acknowledge that this study incorporated merely one study on the improvement of anaerobic performance by l-IHT, undermining the credibility of the results. Accordingly, more related studies are needed in the future to provide evidence-based support. It seems difficult to achieve beneficial adaptive changes in performance with intermittent passive hypoxic exposure and continuous low-intensity hypoxic training.

Use of Inter-Effort Recovery Hypoxia as a New Approach to Improve Anaerobic Capacity and Time to Exhaustion

Putti, Germano Marcolino, Gabriel Peinado Costa, Matheus Silva Norberto, Carlos Dellavechia de Carvalho, Rômulo Cássio de Moraes Bertuzzi, and Marcelo Papoti. Use of inter-effort recovery hypoxia as a new approach to improve anaerobic capacity and time to exhaustion. High Alt Med Biol. 25:68-76, 2024. Background: Although adding hypoxia to high-intensity training may offer some benefits, a significant problem of this training model is the diminished quality of the training session when performing efforts in hypoxia. The purpose of this study was to investigate the effects of training and tapering combined with inter-effort recovery hypoxia (IEH) on anaerobic capacity, as estimated by alternative maximum accumulated oxygen deficit (MAODALT) and time to exhaustion (TTE). Methods: Twenty-four amateur runners performed, for 5 weeks, 3 sessions per week of training consisted of ten 1-minute bouts at 120% (weeks 1-3) and 130% (weeks 4 and 5) of maximum velocity (VMAX) obtained in graded exercise test, separated by a 2-minute interval in IEH (IEH, n = 11, FIO2 = 0.136) or normoxia (NOR, n = 13, fraction of inspired oxygen = 0.209). Before training, after training, and after 1 week of tapering, a graded exercise test and a maximal effort to exhaustion at 120% of VMAX were performed to determine TTE and MAODALT. The results were analyzed using generalized linear mixed models, and a clinical analysis was also realized by the smallest worthwhile change. Results: MAODALT increased only in IEH after training (0.8 ± 0.5 eq.lO2) and tapering (0.8 ± 0.5 eq.lO2), with time x group interaction. TTE increased for the pooled groups after taper (23 ± 11 seconds) and only for IEH alone (29 ± 16 seconds). Clinical analysis revealed a small size increase for NOR and a moderate size increase for IEH. Conclusions: Although the effects should be investigated in other populations, it can be concluded that IEH is a promising model for improving anaerobic performance and capacity. World Health Organization Universal Trial Number: U1111-1295-9954. University's ethics committee registration number: CAAE: 32220020.0.0000.5659.

Effects of six weeks of sub-plateau cold environment training on physical functioning and athletic ability in elite parallel giant slalom snowboard athletes

Background

Hypoxic and cold environments have been shown to improve the function and performance of athletes. However, it is unclear whether the combination of subalpine conditions and cold temperatures may have a greater effect. The present study aims to investigate the effects of 6 weeks of training in a sub-plateau cold environment on the physical function and athletic ability of elite parallel giant slalom snowboard athletes.

Methods

Nine elite athletes (four males and five females) participated in the study. The athletes underwent 6 weeks of high intensity ski-specific technical training (150 min/session, six times/week) and medium-intensity physical training (120 min/session, six times/week) prior to the Beijing 2021 Winter Olympic Games test competition. The physiological and biochemical parameters were collected from elbow venous blood samples after each 2-week session to assess the athletes' physical functional status. The athletes' athletic ability was evaluated by measuring their maximal oxygen uptake, Wingate 30 s anaerobic capacity, 30 m sprint run, and race performance. Measurements were taken before and after participating in the training program for six weeks. The repeated measure ANOVA was used to test the overall differences of blood physiological and biochemical indicators. For indicators with significant time main effects, post-hoc tests were conducted using the least significant difference (LSD) method. The paired-samples t-test was used to analyze changes in athletic ability indicators before and after training.

Results

(1) There was a significant overall time effect for red blood cells (RBC) and white blood cells (WBC) in males; there was also a significant effect on the percentage of lymphocytes (LY%), serum testosterone (T), and testosterone to cortisol ratio (T/C) in females (p < 0.001 - 0.015, η p 2 = 0 . 81 - 0 . 99 ). In addition, a significant time effect was also found for blood urea(BU), serum creatine kinase (CK), and serum cortisol levels in both male and female athletes (p = 0.001 - 0.029, η p 2 = 0 . 52 - 0 . 95 ). (2) BU and CK levels in males and LY% in females were all significantly higher at week 6 (p = 0.001 - 0.038), while WBC in males was significantly lower (p = 0.030). T and T/C were significantly lower in females at week 2 compared to pre-training (p = 0.007, 0.008, respectively), while cortisol (C) was significantly higher in males and females at weeks 2 and 4 (p _(male) = 0.015, 0.004, respectively; p _(female) = 0.024, 0.030, respectively). (3) There was a noticeable increase in relative maximal oxygen uptake, Wingate 30 s relative average anaerobic power, 30 m sprint run performance, and race performance in comparison to the pre-training measurements (p < 0.001 - 0.027).

Conclusions

Six weeks of sub-plateau cold environment training may improve physical functioning and promote aerobic and anaerobic capacity for parallel giant slalom snowboard athletes. Furthermore, male athletes had a greater improvement of physical functioning and athletic ability when trained in sub-plateau cold environments.

The Effects of 15 or 30 s SIT in Normobaric Hypoxia on Aerobic, Anaerobic Performance and Critical Power

Sprint interval training (SIT) is a concept that has been shown to enhance aerobic-anaerobic training adaptations and induce larger effects in hypoxia. The purpose of this study was to examine the effects of 4 weeks of SIT with 15 or 30 s in hypoxia on aerobic, anaerobic performance and critical power (CP). A total of 32 male team players were divided into four groups: SIT with 15 s at FiO₂: 0.209 (15 N); FiO₂: 0.135 (15 H); SIT with 30 s at FiO₂: 0.209 (30 N); and FiO₂: 0.135 (30 H). VO_2max did not significantly increase, however time-to-exhaustion (TTE) was found to be significantly longer in the post test compared to pre test (p = 0.001) with no difference between groups (p = 0.86). Mean power (MPw.kg) after repeated wingate tests was significantly higher compared to pre training in all groups (p = 0.001) with no difference between groups (p = 0.66). Similarly, CP was increased in all groups with 4 weeks of SIT (p = 0.001) with no difference between groups (p = 0.82). This study showed that 4 weeks of SIT with 15 and 30 s sprint bouts in normoxia or hypoxia did not increased VO_2max in trained athletes. However, anerobic performance and CP can be increased with 4 weeks of SIT both in normoxia or hypoxia with 15 or 30 s of sprint durations.