The effect of 8 weeks of repetitive speed training in hypoxia and normoxia on erythropoietin and aerobic performance of athletes.

Introduction: Due to the changes that exercise brings to the body in hypoxic conditions, today hypoxic exercise is one of the most common types of exercise among most athletes, coaches and sports professionals to improve performance at sea level (1). In this regard, various types of hypoxia exercises, such as speed training in hypoxia, have recently been considered. Hypoxia exercises are usually performed in which athletes live at or near the sea level but perform hypoxia exercises at an altitude of 2,000 to 4,500 meters (3). But simulated hypoxia training methods are also used. In this regard, various researches on performance and different variables in athletes of different disciplines in hypoxia have been performed and contradictory results have been obtained. However, changes in body systems due to hypoxic conditions depend on the severity and duration of hypoxia and the type of exercise. As there is still no general consensus in this regard. And researchers have used different training methods and contradictory results have been obtained. One of the training methods considered by researchers is the use of periodic exercises (repetitive speed exercises). In which athletes are exposed to hypoxia in a simulated environment while living in normoxic conditions with discrete and relatively short intervals (5-180 seconds) (11). This model of training can be used by athletes at rest or during core training sessions. The aim of this study was to determine the effect of 8 weeks of repetitive speed training in hypoxia and normoxia on erythropoietin and performance of female boatmen. Methods: The present study is a quasi-experimental study that was conducted by field method with pre-test-post-test design with two experimental groups and one control group. The method of conducting the research was that the researcher first referred to the sailing federation and after explaining the purpose and importance of conducting the research and obtaining the consent of the officials during the sessions, explained the purpose of conducting the research to 14 to 20 year old female sailors in Tehran. In the next stage and after completing the consent form and general health questionnaire, eligible individuals to participate in the study (no history of acute mountain sickness in the last three months and musculoskeletal damage in the last six months) were identified and among the volunteers. 30 patients were randomly selected as a sample and divided into 3 groups: hypoxia (n = 10), normox (n = 10) and control (n = 10). Then, to collect data in the pre-test, all subjects were present in the physical education laboratory of the Faculty of Sports Sciences, University of Tehran for three consecutive days to perform the relevant tests and blood sampling. Blood samples were taken from the subjectchr('39')s left elbow at 8 ochr('39')clock in the morning on an empty stomach. On the second day, the maximum oxygen consumption of the subjects was calculated from the exercise test described by Savka et al. Using a Monarch handheld bicycle for aerobic tests. On the third day, the performance of 500 kayaks of the subjects was measured. Also, to determine the intensity of training in manual ergometer, the subjects were asked to do kayak paddling for 30 seconds. At the end of 30 seconds, the distance traveled and the subjectschr('39') heart rate were measured. Due to the improvement of the subjectschr('39') performance in the ergometer, this test was repeated every two weeks to determine the training pressure. The training program of the hypoxia group, which was performed using a hypoxia device and a mask, consisted of three repetitive speed training sessions on a rowing ergometer with an intensity of 80% of maximum performance in hypoxia conditions. For this purpose, first the subjects started warming up for five minutes with an intensity of 50% of maximum performance on the rowing ergometer, then performed 9 repetitions of 30 seconds with an intensity of 80% of maximum performance for eight weeks. Finally, to cool, the subjects paddled for five minutes at 50% of maximum execution. Also, two of the five sessions of the training program were dedicated to rowing exercises for 90 minutes. The training program of the normoxy group is similar to that of the hypoxic group, except that their activity was performed under normal oxygen conditions with normal oxygen pressure. The group also participated in rowing exercises five days a week. To describe the data from the central tendency indices, to evaluate the normality of data distribution from Shepiro-Wilk test and for inferential analysis of data from composite analysis of variance (2 × 2) and Bonferroni post hoc test using SPSS / 21 software and for The test of research hypotheses was considered a significance level of 0.05. Finally, Excel software was used to draw the charts. Results: The results of combined analysis of variance (3. 2) test showed that the main effect of the measurement steps and the interaction of the measurement steps and the group was on the record of 500 meters kayak for girls, but the main effect of the group was not significant. Due to the significant interaction between the measurement steps and the group, the results of one-way analysis of variance showed a significant difference between the groups in the post-test. Based on Bonferoni post hoc test, it was observed that the hypoxia group was significantly better than the normoxy and control groups, but there was no statistically significant difference between the other groups. It was also found that in the hypoxia group there was a significant decrease in 500 kppa, but in the control and normoxia groups there was no significant difference between pre-test and post-test.Regarding EPO, the results of combined analysis of variance test (3. 2) showed that the main effect of measurement steps, interaction of measurement steps and group and the main effect of group on EPO were not significant. In other words, there was no significant difference between the effect of repetitive speed training in hypoxia and normoxia on EPO. Discussion and Conclusion: In general, the results of the present study showed that training in hypoxic conditions improves the performance of rowing girls and has no significant effect on erythropoietin. Although there is evidence that hypoxia exercise is beneficial for competition at height, specific recommendations are currently difficult until more results on hypoxic exercise performance after hypoxia exercise are available. Therefore, more research is needed in this area. Ethical Considerations Compliance with ethical guidelines All ethical principles were considered in this article. The participants were informed about the purpose of the research and its implementation stages; they were also as sured about the confidentiality of their information; Moreover, They were allowed to leave the study whenever they wish, and if desired, the results of the research would be available to them. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for profit sectors. Conflicts of interest The authors declared no conflict of interest.