## 4 Discussion
Although this study showed significant temporal, but not spatial, changes in gait parameters following heavier load carriage, the perspective of our findings is multifactorial. Based on the results, no significant spatial gait changes occurred even after carrying approximately 50% body mass, indicating that intervention police officers have developed a neuro-muscular adaptation to external heavy load after years of experience and being under constant stressful events and tasks. On the other hand, some of the temporal gait parameters significantly changed, especially in terms of cadence, pre-swing and swing gait cycles. This would imply that a single-legged part of gait under different load conditions may be more prone to changes than other temporal parameters. However, the inability to measure and track intervention police officers prior to entering the service and establish their biomechanical gait characteristics disabled us from comparing and testing the effects of standardized equipment being carried. However, from a practical point of view, we only observed very low partial eta squared, meaning that although significant temporal changes occurred, clinical implications of our data might be not relevant for taking an extra step forward for changing and re-positioning heavy equipment in intervention police officers. Unfortunately, we were unable to test the impact of previous experience of carrying heavy loads; therefore, the findings of this study should be interpreted with caution. Along with this limitation, our study has several limitations. We did not measure gait kinematics or muscle activity properties during walking. Second, a self-selected walking speed can be a compensatory mechanism for altering gait locomotion to accommodate external heavy loads. By using a pre-determined treadmill walking speed, we might have observed different gait changes. Third, the load was not tested independently of how it was distributed on the body. Fourth, the testing procedure was based on walking barefoot, which is not a common practice during specific task performances. By using in-shoe insoles, we would be able to examine the effects in real situations, compared to laboratory testing. In addition to several limitations, this study has strengths. First, we used a relatively new technology to examine spatial and temporal changes in gait biomechanics in intervention police officers, following different load conditions. For instance, the majority of previous studies have conducted their research on military personnel [11], limiting the generalizability of the findings to other special populations. Next, a standardized load equipment was used to determine whether such external load might impact walking characteristics. Finally, compared to previous evidence [11], a relatively large sample was recruited, which gave us the opportunity to test gait differences without the loss of statistical power. Although this study is one of the first to examine changes in spatial and temporal gait parameters in intervention police officers, based on study limitations, future research should be based on investigating these changes in different special populations (police, military, firefighters) and by including kinematics, kinetics, and electromyography properties of the gait under different load conditions, in order to establish global differences and detect these parameters that discriminated between the groups.