## 4 Discussion
[PERSON] and [PERSON] [11] used a hip impact simulator to assess femoral neck force for four energy-absorbing floors and reported that two commercially available compliant floors (SmartCell, SofTile) can attenuate femoral impact force by up to 50% while having only a limited influence on balance in older women. [PERSON] et al. [9] indicated that safety floors demonstrated significantly increased energy absorption (20.7% to 28.3%) compared to a baseline resilient-rolled-sheeting system. [PERSON] et al. [57] used a materials testing system to characterize the ability of floors to absorb energy during simulated head and hip impacts. The results suggest that the safety floors effectively absorb substantial impact energy without increasing football deflections. Numerous reports [13; 58; 59] compared the reduction in head linear kinematics, including peak force and HIC, and determined the protective performance. The results in terms of reduction in angular kinematics and brain strain in this study further illustrate the potential for brain injury risk reduction of EAFs. There are some limitations associated with the current study. Firstly, the FE simulations are implemented without the inclusion of the neck and the rest of the body, which could influence the impact dynamics and kinematics of the head [60; 61; 62; 63; 64; 65]. [PERSON] et al. [16] compared the difference in linear and angular head kinematics between a head-only model and a full-body model during the impact against playground surfaces with various stiffness. The results indicated that the head-only model presented slightly higher values compared to the full-body model [49] in linear kinematics, while the angular kinematics were underestimated by the simplification of excluding the body. It indicated that the current method is conservative if we assume the full-body model more accurately capturesthe actual scenario. More research is needed to understand the influence better. Secondly, the lack of data from real-world fall accidents involving brain trauma is also one of the limitations. Given that only one typical head impact case was selected, fall accidents in the real world can vary greatly. Validation of the head kinematics in several reconstructed cases and statistical analysis of the initial conditions at the impact moment is beyond the scope of the current study but could be considered in future research. Additionally, the drop validation was conducted with a unidirectional impact, while the falls can have a vector of motion that induces shear in the floor material. The oblique loading and mechanical properties in the shear/anisotropic deserve further study. There are also other floor products or variations with different mechanical properties and energy absorption efficiencies that were not specifically examined in this study. Further research could explore these additional options to provide a more comprehensive understanding of the potential range of flooring solutions. Conceptualization, S.K. ; methodology, Q.H. ; software, Q.H. ; validation, Q.H. ; formal analysis, Q.H. ; investigation, S.K. and Q.H. ; resources, S.K. and Q.H. ; data curation, Q.H. ; writing--original draft preparation, Q.H. ; writing--review and editing, S.K. ; visualization, Q.H. ; supervision, S.K. ; project administration, S.K. ; funding acquisition, S.K. All authors have read and agreed to the published version of the manuscript. This research was funded by a grant from Sweden's innovation agency, Vinnova (D.nr. : 2013-04465, 2021-01598). Not applicable. Data Availability Statement: Data is contained within the article. The computations were enabled by resources provided by the Swedish National Infrastructure for Computing (SNIC), at the PDC Center for High Performance Computing, KTH Royal Institute of Technology, partially funded by the Swedish Research Council through grant agreement no. 2018-05973. S.K. has a financial interest in a company aiming to produce safety flooring (Igeldott Golv AB), and both he and the company may benefit from the results of this research.