Effects of Different Types Strength Exercises with Thera-Band ® on Oxidative Stress and DNA Damage

The aim of this study is to determine the effects of both static and dynamic strength trainings on oxidative stress and DNA damage in elite boxers. 19 elite male boxers participated in the study. Boxers were instructed to perform strength exercises 3 days a week for 8 weeks. Blood samples were taken before exercises (resting), after the first exercise (acute) and after 8 weeks following the last exercise (chronic). MDA, SOD, GPx and 8-OHdG levels of blood were examined. Statistical analyses were carried out using the SPSS 22 for Windows. The data were found to not be distributed normally. Thus, Friedman, Wilcoxon and Mann-Whitney U tests were used. The results were evaluated using an alpha level of .05. In the dynamic strength exercise group, there was no significance at GPx, however MDA, SOD and 8-OHdG levels decreased in 8 weeks. In static strength exercise group, although there was no significance at SOD, GPx and 8-OHdG, MDA levels decreased both after a single session and in 8 weeks. In addition, significant difference was found between dynamic and static exercise groups at SOD, GPx and 8-OHdG levels in pre-exercise and at 8-OHdG levels after 8 weeks. Dynamic strength exercises with Thera-Band are effective on MDA, SOD and 8-OHdG chronically, static strength exercises are effective on MDA both acutely and chronically. Neither dynamic nor static strength exercises are not effective on GPx both acutely and chronically.


Introduction
The effects of physical activity on human organism have been revealed in many studies.Different physiological and biochemical results can occur in human body by different forms of exercise (Gursoy et al. 2012;Aggon et al., 2017;Aggon et al., 2018).According to Galvao and Taaffe (2005), elastic band exercises are also effective on the neuromuscular system, improve the muscle strength and power (Galvao and Taaffe, 2005).Exercise can cause the formation of more free radicals by increasing metabolic processes and oxygen consumption in proportion to intensity and duration (Pereirae et al. 1994;Colakoglu et al. 1998;Palmer et al. 2003).For example, superoxide anion radicals (O2-) and hydrogen peroxide (H2O2) increase considerably in maximal exercises (Skinner et al. 1989).Free radicals, which are called as reactive oxygen species (ROS) in general, are very reactive due to these molecules having lone electrons in their outer shells.ROS are the product of normal cellular metabolism (Halliwell, 1991;Turrens, 2003;Chernyak et al. 2006).ROS may affect the structure of body lipids, proteins, carbohydrates, and DNA (Paulson, 1983).In order to prevent the formation of reactive oxygen species and damage, there is an antioxidant defense system.The increase of free radicals is controlled by the antioxidants (such as catalase, superoxide dismutase, glutathione peroxidase).In addition, the duty of antioxidants is to prevent the formation of free radical and make them ineffective (Akkus, 1995;Fisher-Wellman and Bloomer, 2009;Birben et al. 2012).Malondialdehyde (MDA) is the most abundant aldehyde product, and it is one of the markers used to measure the level of oxidative stress (Papas, 1996;Eken, 2011).Both superoxide dismutase (SOD) and glutathione peroxidase (GPx) are antioxidant enzymes.SOD catalyzes the dismutation of superoxide (O2.-) into hydrogen peroxide (H2O2), GPx catalyzes the reduction of oxidized glutathione into reduced glutathione (Michels et al. 1994;Gul et al. 2000;Yang et al. 2002).DNA is an easy target for free radicals (Dizdaroglu et al. 2002).In oxidation, one hydroxyl radical is added to 8th position of guanine molecule and 8-OHdG forms, which is one of the free radical lesions of DNA modified by oxidation (Altuntas, 2007).ROS cause break-off and base modification in DNA string.The predominant basic modification is in guanine, which is, upon oxidation, converted into 8-hydroxy-2-deoxyguanosine .The resulting molecule is used as a marker for DNA damage (Loft et al. 1993;Chang et al. 2011).This study was designed to determine the effects of dynamic and static exercises with Thera-Band® on oxidative stress and DNA damage, which is a new exercise tool.

Experimental Design
The study was divided in two experiments (Fig. 1).
Experiment 1 was designed to evaluate the impact of oxidative stress and DNA damage for eight weeks of dynamic exercise program with Thera -Band (n = 10).
Experiment 2 was designed to evaluate the impact of oxidative stress and DNA damage for eight weeks of static exercise program with Thera -Band (n = 10).

Exercise Tool
Gold Thera-Band for very high-level resistance and silver Thera-Band for high level resistance.

Exercise Protocols
Karakurt's (2017) method was applied in two exerciseprograms in this study.
Dynamic exercise program: Boxers exercised with the Thera-Band for 3 days/8 weeks.Boxers performed this sportive movement as dynamic; direct hit, crochet, uppercut, elbow flexion, elbow extension, sideways lifting, rowing up, flapping, chest press, front lift, cross-lift, cross back cut, leg press, fall off.Muscle contractions were formed by repeating each movement in this group.
Static exercise program: Boxers exercised with the Thera-Band for 3 days/8 weeks.Boxers performed this sportive movement as static; direct hit, crochet, uppercut, elbow flexion, elbow extension, sideways lifting, rowing up, flapping, chest press, front lift, cross-lift, cross back cut, leg press, fall off.Muscle contractions were stable in this group.
All movements were made at the same time in both dynamic and static groups.

Uptake and Conservation of Blood Samples
Blood samples were taken before exercises (resting), after the first exercise (acute), and after 8 weeks the last exercise (chronic).The blood samples were centrifuged at 3000 rpm for 15 minutes and they were stored at -80 °C for subsequent analyses.

MDA, SOD, GPx and 8-OHdG Analyses
Analysis of serum MDA was conducted by high-performance liquid chromatography (HPLC) as described by Khoschsorur et al (2000).Fluorometric detection was performed with excitation at 527nm and emission at 551nm.The peak of the MDA-TBA adduct was calibrated as 1,1,3,3 tetraethoxypropane.Standard solution was prepared through exactly the same process as with the plasma sample.MDA levels were expressed as µM.
The SOD activity was detected according to Sunet al. (1988).In this method, xanthie-xanthine oxidase complex produces super oxide radicals, which react with nitrobluetetrazolium (NBT) to form the farmasone compound.The SOD activity was measured at 560 nm by detecting the inhibition of this reaction.
GPx activity was measured by coupled spectrophotometric assay at 340 nm from the oxidation of NADPH in the presence of H2O2 used as substrate (Aebi, 1984).
Total DNA of leukocytes was extracted in accordance with Miller et al. (1988) and Adeli et al. (1990) with some modification.Nuclear fractions were obtained from 2 mL whole blood with EDTA.DNA aliquots were hydrolysed by Harparkash and Halliwell's method (Harparkash, and Halliwell, 1996).Before analysis by HPLC, they were redissolved in the eluant (final volume 1 ml).In the hydrolyzed DNA samples, 8-OHdG and dG levels were measured by HPLC with electrochemical (HPLC-ECD) and variable wavelength detector (HPLC-UV) systems as previously described (Shigenaga et al. 1994;Armstrong, 1998).The dG concentration was monitored based on absorbance (245 nm) and 8-OHdG based on the electrochemical reading (600 mV).Levels of dG and 8-OHdG were quantified using the standards of dG and 8-OHdG from sigma; the level of 8-OHdG level is expressed as the number of 8-OHdG molecules per 106 dG (Tarng et al. 2000).

Statistical Analyses
Statistical analyses were carried out using the SPSS 22 for Windows.Normalization analysis was performed to determine whether the data were normally distributed.The data were not distributed normally.Thus, K-Related Samples Friedman test was used for the analysis of repeated measurements and for the comparison of pre-and post-exercise data and chronic and acute mode data, 2-Related Samples Wilcoxon test was used in the evaluation of the groups as pairs.In addition, Mann-Whitney U test was used for inter-group comparisons.The results were evaluated on the basis of significance at 0.05.*p≤.05 p: statistically significant different from baseline, MDA: Malondialdehyde (µM), SOD: Superoxide dismutase (IU/mL), GPx: Glutathione Peroxidase (IU/mL), 8-OHdG: 8-hydroxy-2-deoxyguanosine (pg/mL)

Results
In Table 3, dynamic and static exercises performed with thera-band showed significant difference in SOD, GPx and 8-OHdG values in favor of dynamic exercise group and moreover in acute 8-OHdG values significant difference was found in favor of dynamic exercise group while in chronic values no significant difference was observed on any parameter.

Discussion
In this study where we investigated the effects of two different types of exercises performed with thera-band on oxidative stress and DNA damage in elite boxers, both dynamic and static exercises acutely and significantly increased MDA values.In contrast, it was found that static exercises significantly decreased the values in chronic period and in in resting, acute or chronic periods, no significant difference was found between the two exercise group values.
A number of studies in the literature show that the acute effect of exercise on MDA is usually increasing intensitynm (Gullu, 2007;Akil, 2009).Lovlin et al. (1987) in exercises performed at 100% VO2Max intensity and Radak et al. (1995) in exhaustion exercises on the treadmill significant increase in lipid peroxidation values was observed.In one recent study, it was found that resistance exercises conducted for 6 months with elastic band caused oxidative stress (Franzke et al. 2018).
Another study conducted with Thera-Band suggested that both dynamic and static exercises have been reported to be significantly effective on strength values (Karakurt, 2017).Therefore, it was found that Thera-Band use has an effect on the strength and is also effective on oxidative stress.
The present study reveals that dynamic exercises significantly increased SOD values chronically while they had neither acute nor chornic effect though showing a tendency of increase.Significant difference was found in favor of dynamic exercises in values in resting while no significant difference was observed in acute and chronic periods between the groups.Moreover, when GPx values examined, they had no significant effect neither acutely nor chronically though increasing while significant difference was seen in resting values in favor of dynamic exercise groups and no significant difference was seen between the groups in acute and chronic periods.
It has been demonstrated that antioxidant system plays a more important role in the increase of oxygen consumption and the increase of oxidative stress due to the increase of oxygen consumption, both acutely or chronically (İnal et al. 2001;Burneiko et al. 2006;Celik et al. 2007;Kiyici and Kishali, 2010).In one similar study to ours, strength exercises were reported to increase SOD (Vilela et al. 2018).
8-OHdG values, another research problem, which is one of the oxidative DNA damage indicators, decreased chronically with dynamic thera-band exercises; while static exercises had no significant effect neither chronically nor acutely but the effects of dynamic and static exercises on 8-OHdG compared, no significant difference was seen in the chronic period between the groups while there were significant differences in rest and acute periods.When the literature is examined, oxidative DNA damage has been reported in some research results where the exercises are very severe (Tsakiris et al. 2006;Goon et al. 2008;Paik et al. 2009;Hamid et al. 2011).The reason could be that antioxidant mechanisms do not adequately clean free radicals in physical activities carried out in excessive concentrations.In studies where intensity is kept lower and the duration is longer, antioxidant system is more efficient and therefore more effective against oxidative DNA damage.It has been reported that traumatic acute exercises cause DNA damage but regular exercises provide protective adaptations for endogenous antioxidant defense and DNA repair mechanisms (Radak et al. 2002;Cobley et al. 2015).Hamurcu et al. (2010) reported that 8-OHdG values of athletes doing regular wrestling training were lower than the sedentary.Radá k et al. (2000) reported that 8-OHdG values of the athletes who conducted a severe program showed a significant increase at the beginning but they started to decrease at the end of the program.In addition to Parisea et al. (2005) reported that the exercises they performed for 14 weeks resulted in significant decreases in the 8-OHdG amount.

Conclusion and Recommendations
In the present study;  Both dynamic and static exercises performed with thera-band acutely significantly increased MDA values.However, static exercises decreased the values in the chronic period.The effects of dynamic and static exercies were found to be mostly similar in rest, acute or chronic periods.
 Dynamic exercises significantly increased SOD values chronically while static exercises had neither acute nor chronic significant effect.However, they had significant difference in favor dynamic exercise group in resting values.
 It was found that dynamic and static exercises did not have an acute or chronic effect on GPx values, and that the effects of two exercise types were significantly similar in acute and chronic periods.,  Dynamic exercises reduce 8-OHdG values chronically, and static exercises do not have significant acute or chronic effect.
When the results obtained in the study are evaluated in general, we can state that both types of exercises conducted had significant effects on all parameters except on GPx.Today when the use of a wide variety of vehicles with different economic values has become more and more common to do exercise and the use of these ecological and easy-to-reach tools is more and more increasing.Therefore, determining the effects of such vehicles on athletes is among the primary responsibilities of researchers.Therefore, we can suggest that more effective research tools should be invented or used by the researchers.

Table 1 .
Comparison of MDA, SOD, GPx and 8-OHDG Values of the DE *p≤.05 p: statistically significant different from baseline, MDA: Malondialdehyde (µM), SOD: Superoxide dismutase (IU/mL), GPx: Glutathione Peroxidase (IU/mL), 8-OHdG: 8-hydroxy-2-deoxyguanosine (pg/mL) When Table I is examined, dynamic exercises with thera-band significantly reduced MDA, SOD and 8-OHdG values, but did not have an acute significant effect while it is seen that there is an increase in GPx values, although it does not have a significant effect at either acute or chronic level.

Table 2
examined, it was observed that static exercises performed with thera-band acutely significantly increased MDA values while they decreased them in the chronic period; it did not have an acute or chronic effect on SOD, GPx and 8-OHdG values.

Table 3 .
Comparison of Dynamic and Static MDA, SOD, GPx and 8-OHDG Values in Resting, a Single Session and 8 Weeks