## 4 Discussion
A similar increase in RBC and HGB during walking at the DT and fetlock-depth WT, along with elevated HR 30 min post-exercise during the DT session, may also be attributed to a stress response. Similar to the [PERSON] et al. [2] study, the variation in HR recovery times may be a result of differing stress levels. This is likely because the DT exercise was the first measured session following the completion of WT habituation. Previous studies have indicated that two habituation sessions to the WT exercise protocol are sufficient to ensure accurate physiological measurements [27]. In this study, however, three habituation sessions were conducted, following the protocol described by [PERSON] et al. [23]. To further investigate the effects of WT exercise with AR, future studies should consider including cortisol measurements in blood or saliva as quantifiable indicators of stress in horses [39]. The absence of significant differences between exercise sessions for any of the measured physiological response indicators at the pre-exercise time point suggests that this study was well-designed, aligning with methodologies from previous publications [2; 23; 24; 27; 35; 40]. However, awareness of the strengths of prior research highlights the limitations of this preliminary study. Physiological responses were measured in a group of warmblood school horses, which may limit the generalizability of the findings to other breeds or disciplines, such as show jumping [3; 4; 30], dressing [3; 4], evening [4], or barrel racing [23], as investigated in earlier studies. Extrapolation may also be challenging for Thoroughbreds [2; 16] or Arabian horses [28], given that the physiological demands of school horses only partially align with those of endurance or racehorses [40]. Moreover, the block-assigned treadmill sessions, progressing from the least demanding DT exercise to the more demanding WT exercises with increasing water resistance, do not meet the criteria for a randomized controlled trial [41]. The decision to block the training sessions was made to limit the impact of stress on the horses [23; 27], which could influence the results due to the progressively increasing workload. However, a certain effect resulting from this blocking approach is to be expected. To minimize this effect, WT exercise sessions were conducted once per week, allowing sufficient time for hematological and biochemical indicators to return to baseline levels. For this reason, the study should be considered preliminary, ranking lower on the Evidence-Based Medicine Ratings scale [41]. Future studies should aim to adopt a randomized model, if feasible, to strengthen the level of evidence. Despite these limitations, the current findings provide insights that may aid in designing WT+AR exercise protocols for horses engaged in full sport or racing activities. These results could serve as preliminary guidelines for incorporating AR mode into equine training or rehabilitation protocols. However, because physiological responses were measured exclusively in healthy horses, the applicability of these findings to horses with pathological conditions remains uncertain. Further research is needed to evaluate the suitability of WT+AR exercise for conditioning and rehabilitation, particularly through more extensive research protocols. This would address the study's primary limitations, including the lack of kinematic data [4; 12; 13; 14; 15; 16; 17; 18; 19; 25] and ergospirometric measurements [2; 23]. While this study demonstrated that incorporating AR into WT exercise increases workload intensity, it cannot yet be recommended for specific training or rehabilitation applications until further data on kinematic responses, muscle activity, and cardiorespiratory responses are available. Future research should investigate whether AR increases step length, limb protraction and retraction, joint flexion, and dorsoventral displacement of the back [4; 12; 13; 14; 15; 16; 17; 18; 19; 25].