The Effects of Combined Training on Oxidative Stress and Antioxidant Defense Indicators

Sports science is a new discipline that has been introduced to the world in recent years through the works of scientists and researchers interested in this realm. This discipline is growing in demand due to its different uses and a variety of applications, and almost all the people and social institutions are getting involved with this field of study.1 The state of imbalance between generation of reactive free radicals and the antioxidative capacities detoxifying their detrimental effects is called oxidative stress. The shift in the balance between oxidants and antioxidants in favor of oxidants is termed “oxidative stress.”2 Stress oxidative can damage tissues, cells and macromolecule of cells like lipids, proteins and nucleic acids. Thus, oxidative stress leads to many conditions in the body like reduction in physical performance, chronic fatigue, tissue damage and over training.3 Antioxidants are molecules that protect biological systems against chain reactions that lead to oxidation.4 A variety of studies have focused on exercises with different protocols on antioxidant and oxidative stress indicators. Firoozrai et al found that cell membrane of red blood cells and maybe other body cells is less susceptible to damage among athletes indicating that the balance between antioxidants and oxidative stress is more suitable among athletes than among other people.5 Gaeini et al showed that after one session of endurance doi 10.15171/ijbsm.2017.07


Introduction
Sports science is a new discipline that has been introduced to the world in recent years through the works of scientists and researchers interested in this realm.This discipline is growing in demand due to its different uses and a variety of applications, and almost all the people and social institutions are getting involved with this field of study. 1 The state of imbalance between generation of reactive free radicals and the antioxidative capacities detoxifying their detrimental effects is called oxidative stress.The shift in the balance between oxidants and antioxidants in favor of oxidants is termed "oxidative stress." 2 Stress oxidative can damage tissues, cells and macromolecule of cells like lipids, proteins and nucleic acids.Thus, oxidative stress leads to many conditions in the body like reduction in physical performance, chronic fatigue, tissue damage and over training. 3Antioxidants are molecules that protect biological systems against chain reactions that lead to oxidation. 4 variety of studies have focused on exercises with different protocols on antioxidant and oxidative stress indicators.Firoozrai et al found that cell membrane of red blood cells and maybe other body cells is less susceptible to damage among athletes indicating that the balance between antioxidants and oxidative stress is more suitable among athletes than among other people. 5Gaeini et al showed that after one session of endurance training malondialdehyde (MDA) reduced compared with control group. 6Dantas et al showed a reduction in MDA and an increase in total antioxidant capacity (TAC) after strength training among elderly women. 7In another study Pedersen et al indicated that daily taking of methylsulfonylmethane supplement for 10 days can reduce muscle damage by affecting TAC in healthy men. 8he biological effects of oxidizing compounds in the body are controlled by antioxidant factors.Dysfunction of the organs might be due to reactions of free radicals with cell membrane.It is known that the main aim of oxygen radicals is the lipids in cell membrane.Human body tissues just like Erythrocytes contain important antioxidants such as glutathione peroxidase and glutathione, therefore normal erythrocytes can resist better oxidative damages. 9ue to lack of relevant literature related to the effect of combined training on the above-mentioned indicators, in this research we intend to analyze the effect of combined training (resistance and endurance) and the interaction between oxidative stress and antioxidant defense.In addition, we aim to find the answer to the following questions: 1. Does an 8-week combined training (resistance and endurance) have a significant effect on oxidative stress and antioxidant defense indicators among sedentary boys? 2. Do we see a significant change due to training compared to the control group?

Methods
In this quasi-experimental study the statistical population included all the boys in Zahedan Youth Detention Center with the age range between 15 to 25 years old.From this population, 23 boys volunteered to participate in the research and were divided randomly into 2 groups (13 in the training group and 10 in the control group).Subjects were first introduced to the aims and process of the research then they were asked to fill out and sign a consent form.In order to avoid any interrupting factors that might affect the study outcomes, subjects were checked regarding their well-being before research initiation.In addition, medication use and suffering from a special disease were taken into account.By the same token a medical health questionnaire was filled by the doctor for each participant.Subjects in the control group were asked not to take part in any physical activity during the time the protocol was being experimented.1). 12sistance Training Protocol The resistance training program included bench press, legs, shoulders, squat and armpit which were done in a circular way.In the first week of training, exercises with 40% to 50% one repetition maximum (1RM) were performed then they increased to 50% to 55%, 55% to 60%, 60% to 65%, 65% to 70%, 70% to 75%, 75% to 80% and 80% to 85% 1RM for second, third, fourth, fifth, sixth, seventh and eighth weeks, respectively. 13ood Biochemical Measurements Blood samples were taken after 8-10 hours of fasting between 7 am to 9 am in the morning in 2 stages; one day before the beginning of the training and 48 hours after the last training session.Blood was taken from the right arm of each participant while sitting in a relaxed manner.About 10 mL of blood was taken and the sera were separated immediately by using centrifugation with the speed of 3000 rpm for 5 minutes.

Results
Findings showed that the amount of MDA decreased and the amount of TAC increased in the experimental group.Table 2 shows the mean and standard deviation of variables.The average amount of MDA and TAC in control group did not change significantly when comparing pretest and post-test results.In order to analyze the difference in the amount of MDA and antioxidant capacity between the control and training group, independent t test was used and the results of this test showed that the difference between the 2 groups was significant.

Discussion
The results of the current study with respect to TAC and MDA indicate that MDA amount after 8 weeks of combined training decreases significantly and the amount of TAC increases as well.
Concerning TAC, our findings are in line with the results of previously conducted studies.Farzanegi et al described that levels of TAC increased while MDA decreased following 6 weeks of aerobic training in postmenopausal women affected with hypertension. 14Jamurts et al also observed an increase in TAC marker in all training groups and a decrease in MDA just in the endurance training group due to resistance and endurance exercises which were held 3 times per week for 6 weeks among the sedentary elderly. 15In addition, long-term sports activity in a study by Padayatty et al demonstrated an increase in TAC which caused an imbalance in pro-oxidants and antioxidants. 16In another study an increase in the activity of antioxidant enzymes and a decrease in the level of MDA in hippocampus of diabetic male rats had beneficial effects in preventing neurological complications of diabetes mellitus and tissue damage due to oxidative stress caused by this disease. 17In a study by Fakoori Jouybari et al a decrease in MDA in relaxed levels and an increase of TAC in all three experiment groups due to 8 weeks of aerobic exercise with purslane seeds consumption on pro-oxidant and antioxidants indicators among women with type 2 diabetes were observed. 180 A variety of mechanisms in explaining the TAC reaction to exercise shows that after intense sport trainings an increase in oxidative stress is caused but combined trainings decrease production of free radicals if done continuously. 21Therefore, MDA decreases as an indicator of lipid pro-oxidation.After the reduction of oxidative stress in body, antioxidant defense system in order to balance with combining resistance and endurance training in a several months' period activates and this increase needs consumption of anti-oxidant supplements to have more effects. 21The most important result of this study is the effectiveness of combined training which has a positive effect on oxidative stress and antioxidant defense indicators by decreasing MDA and increasing TAC.

Conclusion
According to the findings of this research, combined training (resistance-enduring), causes a reduction in oxidative stress markers such as MDA.The reduction of this indicator is accompanied with an increase in TAC.Thus, such trainings to improve the anti-oxidation capacity are suggested.However, to understand the effects of these trainings in different times and combined with anti-oxidation supplements, doing more research will be helpful.

Ethical Approval
This

Table 1 .
10Endurance Training Protocol 19obably, existence of resistance training in this research and its combination with endurance training had more compatibility with this indicator, while in the study of Firoozrai et al due to lack of resistance training such a compatibility was not achieved.Also, Marzatico et al found that MDA levels in plasma increased 48 hours after fast activities among fast athletes and immediately after endurance activity in marathon runners.19Thisfinding is not in line with the results of the present research.We can conclude that this increase is on account of shorter period of time in training protocol or because of existence of a fast training protocol in the above-mentioned research.In a study by Park et al which analyzed the impact of aerobic and anaerobic exercise training on oxidative stress and antioxidant defense in athletes, MDA increased and TAC decreased which is inconsistent with our results.This difference can be due to different levels of physical readiness in the studies as well as subjects which were athletes.
study has been reviewed by the Research Ethics Committee of Sport Sciences Research Institute and was approved according to compliance with Ethical Standards in Research of the Ministry of Science, Research and

Table 2 .
The Mean and Standard Deviation Values of the Studied Variables in Experimental and Control Groups a Significant at P < 0.05.