## 4 Discussion
### Impact of Acceleration/Deceleration  
The current study was also the first which examined the role of glyometric activities (acceleration/deceleration) during HIIT in determining oxidative stress parameters. The results of the current research indicate that oxidative stress was not significantly modified due to the acceleration and deceleration components of the activity performed. However, since no direct comparison (i.e., HIIT including glyometric exercise patterns) to the existing literature could be made, comparisons with eccentric exercise (which imitates, as much as possible, the acceleration/deceleration during running pattern) research investigating oxidative stress are discussed. Interestingly, [PERSON] et al. [38] showed that individuals performing acute eccentric exercise aiming to induce oxidative stress had varied mean responses. It was observed that some individuals experience negative responses, while others experience no increases in the oxidative stress biomarkers tested (F\({}_{2}\)-isoprostanes, protein carbonyls, and glutathione). Thus, due to great heterogeneity, basal levels of the biomarkers of oxidative stress are considered important when these parameters are examined [38]. Although in the study by [PERSON] et al. [38], as well as in the current study, there were no samples from muscle biopsies, it is possible that the structural damages caused to the muscle due to the eccentric nature of the exercise were more prominent in the muscle compared to blood biomarkers of oxidative stress. However, previous findings support that eccentric exercise does not increase glutathione status [39]. This is possibly due to insufficient exercise stimulus, which is also supported by the current study, as total glutathione levels in the current study were not also increased. Similarly, [PERSON] et al. [40] investigated blood oxidative stress biomarkers and conducted muscle biopsy analysis to determine the responses to squat resistance exercise versus sprints. They found minimal modifications in oxidative stress levels between these exercise conditions, suggesting that this is evident when the participants are relatively well trained. In addition, a systematic review found that engaging in running exercises does not trigger a reaction in specific biomarkers associated with oxidative stress [4]. Instead, the expression of oxidative damage markers in lipids, proteins, and various enzymatic and non-enzymatic antioxidants varies based on the individual's training status [4]. In the current study, the participants were relatively well-trained recreational athletes. Consequently, taking the current and the above-mentioned results collectively could imply that relatively well-trained individuals possibly have experienced adaptations due to their training status, leading to non-significant modifications in their oxidative stress levels following submaximal HIIT and glyometric exercise. Supporting this outcome, research examining blood biomarkers and muscle biopsies showed that even exhaustive resistance exercise in trained men showed no upregulation of oxidative stress, as indicated by F\({}_{2}\)-isoprostanes [41]. According to [PERSON] et al. [41], this result could be due to different modes of exercise causing different mechanical stresses that may affect the levels of oxidative stress. [PERSON] et al. [42], for example, investigated the role of eccentric exercise in participants with homogenous muscle fibre type compositions and found that the fibre type composition may influence oxidative stress levels, as correlations existed between type II muscle fibres and protein carbonyls. Consequently, it is possible that individuals with a higher percentage of type II muscle fibres could show higher oxidative stress compared to individuals with type I muscle fibres [42]. As the literature shows [38; 40; 41], the association between eccentric exercise and individual responses, along with the physical performance level of the participants and the physiological stimuli,may significantly influence oxidative stress levels.