## 3 Results
### Lateral Single-Leg Jump Landing
However, our findings are supported by [PERSON] et al., who found that a high collar football shoe effectively reduces the amount of inversion by 4.5\({}^{\circ}\) (38.1\({}^{\circ}\) vs. 42.6\({}^{\circ}\)) after an inversion platform drop [17]. It is possible that a self-initiated drop landing on an inversion platform does not reach the limitation boundary of the inversion for a high collar basketball shoe. During side-step cutting, [PERSON] et al. and [PERSON] et al. found that the ankle inversion angle, peak inversion velocity, and total inversion ROM are reduced as collar height increases [11; 12]. Therefore, there is a restricted angle for an inverted ankle joint position, which might effectively increase ankle joint stability and reduce the risk of ankle sprain injury [11; 12]. In our study, the dorsiflexion and total sagittal ROM showed moderate-to-large effect sizes with the high collar, compared to the other collars. Therefore, the football shoe's higher collar height used in this study could constrain ankle dorsiflexion and the inversion angle during both longitude and widthwise tasks, potentially reducing the risk of ankle sprain injury. Several prior studies have examined the effect of collar conditions on ankle kinetics. [PERSON] et al. detected no difference from collar conditions on the ankle inversion moment during side-step cutting [12]. In addition, [PERSON] et al. reported that high collar basketball shoes could reduce the plantarflexion moment during lay-up jumps, but not drop jumps [13]. The authors suggested that these differential findings were caused by different upper limb positions, movement patterns, and force requirements, as well as the coordination of active and antagonist muscles [13]. These findings are in agreement with our results showing either no significant change or a small effect size in the ankle inversion moment for both tasks; however, different jump maneuvers that are high-frequency and risky during practices or matches still need to be tested. Interestingly, ankle joint stiffness was significantly increased when wearing the high collar football shoe, compared to the other shoes. Theoretically, ankle joint stiffness is calculated using the change in joint moment divided by the change in joint angle [35]. Although the change in ankle moment was not measured in our study, it is possible that the enhanced ankle joint stiffness from the high collar football shoe may be due to a decrease in total ankle ROM in the sagittal plane. Given the primary role that joint stiffness plays in lower limb injuries [38], overuse injuries at the ankle joint might increase as collar height increases. Our findings also suggest that MLSI is improved as the height of the football shoe collar increases. A couple of studies have examined the effect of collar height on static or dynamic postural stability [18; 39]. However, according to previous research, adequate dorsiflexion ROM is essential for dissipating the ground reaction force [40] and has a positive influence on DPSI [30]; these findings conflict with the results of our study. However, evidence from ankle taping and bracing indicate an increased sense of confidence and stability [24]. Inconsistent findings across studies regarding the dynamic stability of ankle taping or bracing might be due to subjects with or without injury [25; 26; 27; 28]. Furthermore, although the current study showed a significant difference in MLSI between shoe conditions during lateral single-leg jump landings, post hoc analysis indicated no pairwise difference, and small effect size. Therefore, this phenomenon still needs to be confirmed, and additional quantitative studies on DPSI are warranted. There are some limitations to the present study. First, only healthy male college football players were recruited as subjects. Players with functional ankle instability may have different responses to shoe collar conditions, especially for DPSI. Second, it should be noted that our current findings were limited to anterior and lateral single-leg jump landings.