Gender differences in footwear characteristics between half and full marathons in China: a cross-sectional survey

There are concerns about the risk of injuries caused by marathons in China. Since male and female runners have different injury risks, gender differences in running shoe functionality should be further complemented. A supervised questionnaire survey of 626 marathon runners was collected. The questionnaire was categorized into four sections: (1) participant profile, (2) importance of shoe properties, (3) functional evaluation of shoe properties and (4) importance ranking of shoe properties. The Mann–Whitney U test, Fisher’s exact test of cross tabulation and Chi-square test, and two-way ANOVA were used to analyze the results of this survey. The significance level was set at P < 0.05. The full marathon participants were older than the half marathon participants. There was no gender difference in the importance of shoe features to elite runners. In addition, women are more concerned about upper elasticity and have higher requirements for running shoes than men. Women were more focused on injury prevention, while men were more focused on running performance. Heel cushioning was identified by all participants as the most important running shoe feature. There were no gender differences between elite players’ demand for running shoes, but significant gender differences were found between genders at other running levels.

Instruments and data collection.Data were collected through a supervised questionnaire that consisted of four sections.The questionnaire was categorized into four sections: (1) participant profile, (2) importance of shoe properties, (3) functional evaluation of shoe properties, and (4) importance ranking of shoe properties.All questionnaires were conducted after the participants finished the competition.
In the first section, participant profiles were obtained, including information such as gender, age, body height, body weight, race distance (full Marathon (42.195 km) or Half Marathon (21.0975 km)), and finish time.
The second section assessed the importance of various shoe properties as common requirements during running.The evaluated variables included forefoot curvature, forefoot bending stiffness, forefoot elasticity, heel curvature, heel cup, heel height, heel cushioning, midfoot anti-twist, midsole hardness, midsole thickness, outsole grip, guidance line, insole shape, upper breathability, upper elasticity, carbon fiber plate, shoelace, and shoe mass.Participants indicated their preferences on a 5-point Likert scale, ranging from 1 (Strongly unimportant) to 5 (Extremely important).
In the third section, participants were asked to evaluate whether specific shoe properties improve running performance or prevent sports injuries.The shoe properties assessed were the same as those in section two, and participants provided ratings using references A (Not important for running performance or preventing injuries), B (Important for running performance), C (Important for prevention of injuries), and D (Important for both running performance and prevention of injuries).The fourth section involved participants ranking the importance of shoe properties, and they selected the top three properties they deemed most important.

Data validity and collection.
To ensure the consistency and reliability of the factor loadings, Cronbach's α coefficient was employed in this study, resulting in a value of 0.874, which indicated acceptable reliability of the questionnaire.The suitability of the data for factor analysis was assessed using the Bartlett spherical test and the Kaiser-Meyer-Olkin (KMO) test.The KMO value of 0.905 indicated that the questionnaire data were suitable for factor analysis.Furthermore, the Bartlett's test result (X 2 = 3017.032,df = 153, P = 0.000) confirmed the necessity of the analysis.
The questionnaire was administered in the field, and participants completed it under the supervision of researchers who provided guidance to ensure the validity of the data.Researchers explained the definitions of footwear and foot-related terminology to avoid misunderstandings, particularly for participants with limited knowledge of footwear construction.Additionally, researchers ensured that participants did not provide random or missing answers, thus maintaining the questionnaire's quality.All questionnaires were completed after participants finished the competition.

Data analysis.
Descriptive statistics were used to describe the characteristics of the participants in the first section of the study.The Kolmogorov-Smirnov test was conducted on the data from the second and third sections, which revealed that the data did not conform to a normal distribution (P < 0.05).Therefore, non-parametric tests were used for further analysis.The Mann-Whitney U test was employed to analyze gender differences in the "Importance of shoe properties" section, and Fisher's Exact Test of Cross tabulation and Chi-square test were used for the analysis of the "Functional evaluation of shoe properties" section.Two-way ANOVA was used to analyze the interaction characteristics of gender and race within the context of our cross-sectional survey investigating gender differences in footwear characteristics between half and full marathons in China.The significance level was set at P < 0.05.All statistical analyses were performed using SPSS 21.0 (SPSS Inc., Chicago, IL, USA).All figures in this study were created using Origin 2021 (OriginLab Corporation, Northampton, MA, USA).

Result
Characteristics of the participants.A total of 626 questionnaires were collected in this study.The basic information of the participants is presented in Table 1, and all respondents gave informed consent and participated voluntarily.As shown below, most runners were males (76.2%), male and female participants in the full marathon were older than the half marathon, and females had lower body mass index (BMI) values than males.
Furthermore, this study used two-way ANOVA to analyze the interaction characteristics of gender and race in this survey, and found that there was no interaction between gender and race items on BMI [F (1,622) = 1.789,P = 0.182, η 2 = 0.002].The main effect analysis showed that gender (F (1,622) = 34.290,P < 0.001, η 2 = 0.052) and race events [F (1,622) = 1.789,P < 0.05, η 2 = 0.008)] had significant effects on BMI, respectively.For race items, the BMI values of males in both the full marathon and half marathon were significantly higher than that of females (P = 0.001, 0.000).For gender, males who participated in the half marathon had a significantly higher BMI value than the full marathon (P = 0.001), but there was no significant difference in females.
Importance of shoe properties.In Table 2, females were more concerned about upper elasticity than males, and females' demand for running shoes was generally higher than males.The Mann-Whitney U test found no gender differences in evaluating the importance of shoe properties by elite-level runners in the full marathon.Compared with first-level male runners, females rated forefoot bending stiffness and upper elasticity as higher importance (P = 0.044, 0.001).For second-level runners, females reported higher importance of midsole hardness and upper elasticity than males (P = 0.024, 0.007).In addition, the importance scores of upper elasticity and shoelace in the third-level female runners were significantly higher than those of the male runners (P = 0.043, 0.046).
For half-marathon runners, there were no gender differences in the evaluation of shoe properties' importance between elite-level and second-level runners, and the differences were mainly found in first-and third-level www.nature.com/scientificreports/participants.Table 3 showed that the importance score of forefoot elasticity for first-level female runners was significantly lower than that of males (P = 0.034).Third-level female runners rated upper elasticity as more important than males (P = 0.017), while third-level males reported higher importance of carbon fiber plate and shoe mass (P = 0.028, 0.022).
Functional evaluation of shoe properties.The Fisher's Exact Test was used to compare males' and females' functional evaluation of shoe properties.This study found no gender differences in elite-level runners' functional evaluations of shoe properties for full-marathon runners.There were significant gender differences in functional assessments of first-level runners in outsole grip, upper elasticity, shoe mass, and guidance line (P = 0.048, 0.002, 0.015, 0.001), as shown in Fig. 1.
Further conducted pairwise comparisons found that for outsole grip, 57% of males believed that this property was important in improving running performance, significantly higher than 32% of females (Fig. 1).Conversely, 44% of females thought the outsole grip was important for preventing sports injuries, more than 21.1% of males.Compared with 4% of females, 35% of males believed that the upper elasticity was neither beneficial for improving running performance nor preventing sports injuries.However, 32% of women felt the upper elasticity was important for preventing sports injuries, significantly higher than 14% of males.In addition, 7% of males thought shoe mass was important for preventing sports injuries, markedly less than 24% of females.44% of females believe that the importance of the guidance line was reflected in preventing sports injuries, and 4% of females considered that this property could prevent sports injuries and improve running performance, which was significantly higher than that of males.
Second-level participants' functional evaluation of shoe properties found significant gender differences in outsole grip and midsole hardness (P = 0.046, 0.025), as shown in Fig. 2. For the outsole grip, 21.9% of males reported that the property was not crucial for running performance and injury prevention, and only 4.3% of females agreed with this, a significant difference.In contrast, 8.7% of females rated the characteristic as necessary for running performance and injury prevention, significantly more than 1.9% of males.Their evaluation of the function of midsole hardness was similar, males (30.5%) who rated that midsole hardness was not crucial for both running performance and injuries prevention significantly over females (8.7%), and females who considered that midsole hardness was necessary for both running performance and injuries prevention (13%) were significantly more than males (2.9%).
Fisher's Exact Test showed no gender differences in functional evaluations of shoe characteristics between elite and second-level runners for half-marathon participants.However, gender differences existed between first-level and third-level runners.
Specifically, there was a significant gender difference (P = 0.012) in the functional evaluation of outsole grip for first-level runners in the half marathon.A pairwise comparison found that 45.8% of females and 14.3% of males rated this feature unimportant for running performance and injury prevention (Fig. 3).The proportion of females was significantly higher than that of males.In addition, 50% of males considered that the property of

Importance ranking of shoe properties.
This study used descriptive statistics to conduct frequency statistics on the importance of shoe characteristics ranked by males and females in the full marathon and half marathon, respectively.Both males and females agreed that "heel cushioning" was the most critical running shoe feature, but there were differences in the ranking of other shoe features.
Specifically, the three properties that male full marathon participants rated as the most important were "heel cushioning, " "forefoot elasticity, " and "shoe mass." The top three shoe traits for females were "heel cushioning, " "midfoot anti-twist, " and "forefoot bending stiffness, " as shown in Fig. 5.In addition, half-marathon participants identified "heel cushioning," "midfoot anti-twist," and "forefoot elasticity" as the three most important characteristics of shoes, as shown in Fig. 5. Furthermore, upon analyzing the data separately for male and female participants, we found that female participants rated "shoe mass" as one of their top three preferred characteristics, while male participants favored "forefoot elasticity" and "forefoot bending stiffness" as their preferred features".

Discussion
In this study, we observed a significantly higher number of male participants completing marathon races compared to females.According to the "2019 China Marathon Big Data Report" released by the Chinese Athletics Association, the number of participants increased by 14.28% in 2019 compared to 2018.Among them, the number of male participants in China was considerably higher than females.However, in the half marathon races, the number of female participants exceeded that of males, aligning with the findings of our study but contrasting with the trend observed in the United States 28 .These findings highlight the gender disparities in marathon participation in China, with a higher proportion of males in the full marathon category and a higher engagement level of females in the half marathon category.
To better understand the reasons behind these gender differences, it is important to consider factors such as motivation and demographics.The "2019 China Marathon Big Data Report" revealed that male full marathon runners in China were more motivated, accounting for 74.63% of all male participants.In our study, we found a similar trend, with 73% of male participants completing the full marathon.In contrast, the percentage of male participants in the half marathon was 27%, while females accounted for 53% of all female participants.These findings suggest that in Chinese marathon events, there is a significantly higher number of male participants in the full marathon category compared to females, while female participants demonstrate a higher level of engagement in the half marathon category.
Furthermore, our study explored the age distribution of marathon participants and found that female participants were older than male participants, with an average age of over 35 years old.This result is consistent with the analysis of the age group of Chinese marathon runners from 2016 to 2019, indicating that the primary finishers of Chinese marathons are predominantly middle-aged individuals.Several factors, including physical and mental needs, social influence, and disposable time, may contribute to this age distribution 29 .
In addition to age, we also examined the influence of gender and age on athletic performance.It was observed that regardless of gender, participants who completed the full marathon were older compared to those who completed the half marathon.This finding suggests that older participants are more inclined to participate in longer endurance sports, reflecting their greater emotional control and sense of responsibility for completing tasks 5,30 .
Another aspect we investigated was the relationship between participants' BMI and their involvement in marathon races.We found that the BMI values of male full marathon participants were significantly lower than those of half marathon participants, and the BMI values of female participants were significantly lower than those of male participants.Previous cross-sectional studies have suggested that BMI contributes to the risk of running-related injuries in population samples [31][32][33] .More specifically, a low BMI even increases female runners' risk of lower extremity injury 31 .Specifically, a low BMI increases the risk of lower extremity injury in female runners due to their tendency to have lower body fat percentages compared to non-marathon females 32,33 .Although some studies have shown no direct association between participants' BMI and injury risk, considering BMI as a potentially modifiable risk factor becomes relevant if it is influenced by marathon activity 34 .
Moving on to the preferences for shoe characteristics among elite runners, we found no gender differences in these preferences in both the half and full marathon categories.This observation indicates that elite runners, regardless of gender, possess a comprehensive understanding of shoes after extensive training sessions and consistently prioritize shoe properties that enhance athletic performance 35,36 .Their knowledge enables them to select more suitable running shoes that align with their specific running requirements 35,36 .
Forefoot bending stiffness is a crucial factor in footwear performance development 37 , and it plays a significant role in maintaining both comfort and performance in running shoes 38 .Furthermore, it has been observed that increasing the forefoot bending stiffness in footwear can reduce the extent of metatarsophalangeal joint extension during movement 39 .In our study, female marathon participants consistently ranked forefoot bending stiffness as their third most important consideration, indicating a higher expectation for this characteristic compared to males.These findings highlight the significance of forefoot bending stiffness in meeting the specific needs and preferences of female runners.Previous studies on gender differences in Chinese foot shape show that Chinese females have a lower first-toe height than males 19 .Therefore, females wearing running shoes with the same forefoot bending stiffness at the same running interface need to generate a larger metatarsophalangeal joint moment, which is more likely to increase the risk of injury of metatarsal stress fractures 39 .The subjective reports of female runners also underscore this point.
Additionally, female full marathon runners expressed a higher level of concern about the upper elasticity of running shoes compared to males.Previous studies have shown that upper elasticity is a critical factor affecting comfort and may impact shoe choice preferences 40 .Biomechanical studies have also shown that changes in the upper elasticity can even lead to changes in running patterns 41 .This preference for footwear comfort aligns with the notion that for runners, emotional value and overall experience hold significance, alongside athletic performance 42 .
Moreover, our study analyzed the preferences of runners based on their finishing times and identified specific characteristics that different levels of runners prioritize.For instance, female three-level finishers, who took the longest to finish the race, emphasized the necessity of shoelaces.This preference aligns with the idea that shoelaces allow for a more comfortable shoe fit, enabling runners to adjust the tightness to obtain a custom fit that accommodates the shape of their foot 43 .Therefore, the fit design of shoelaces is vital for marathon runners, www.nature.com/scientificreports/as increased long-distance running time may lead to increased foot movement in the shoe, and ill-fitting laces can cause blisters and subungual hematomas 44,45 .
In this study, full-marathon first-level males emphasized forefoot elasticity significantly more than females 46 .Studies have shown that changing the flexibility of the forefoot area of a running shoe can provide a greater range of motion in the forefoot and increase activation of the calf muscles 47,48 .Chen et al.'s research showed that increasing the forefoot elasticity of the soles of running shoes can reduce the activity of muscles 49 , thereby reducing energy consumption and improving exercise performance.In the half marathon, the first-level male participants also emphasized forefoot elasticity compared with females, which was consistent with the statistics for full-marathon participants.
A study has examined the impact of shoe mass on preference, performance, and biomechanical variables 50 .In another study, it was found that for every 100g reduction in shoe weight, running economy improved by 1% and running performance improved by 0.7% 51 .In this research, third-level males reported higher importance of shoe mass.Specifically, heavier footwear reduced comfort in second and third-level runners and increased energy requirements at all running levels, potentially reducing preference 52 .Heavier shoes had a significant effect on ankle angle, ankle moment 53 and plantar pressure (second and third-level runners) 54 , which is consistent with the results of this study.
In the "Functional evaluation of shoe properties" part, females were more concerned about whether these properties were necessary for injury prevention, while males were more concerned about the importance of shoe properties to running performance, which may be because females' shoe lasts usually downsized versions of males' shoe lasts, and women rarely buy suitable shoes when purchasing running shoes, and inappropriate shoes will increase the risk of injury during running 16 .However, males can usually buy shoes that fit their feet and preference, which can improve sports performance.
Heel cushioning was reported in this study as the most critical function for all participants, which is an essential function of running shoes.Robbins et al. suggest that the increased cushioning in running shoes can attenuate the perceived magnitude of forces acting on the foot plantar surface 55 .The study by Mark et al. showed that runners (rearfoot strike pattern) used the same pair of running shoes to run 480 km, and the amount of heel cushioning of the rear running shoes would be reduced by 16% to 33% 56 .Based on previous research results by Taunton et al., heel support and cushioning function will decrease with running shoes, and the risk of longdistance running injury will increase 57 .Therefore, stabilizing the heel cushioning performance of running shoes is significant for preventing injuries.In addition, male and female participants in the same schedule have different attributes of shoes ranked second and third, and the same-gender participants of different programs also have different opinions.Based on our findings and previous studies, it is important to consider specific characteristic designs in running shoes for different genders and different race distances.For example, our results had shown that female runners may benefit from shoe designs that address factors such as heel cushioning, midfoot antitwist, and shoe mass.On the other hand, male runners in marathon races have shown a preference for shoe characteristics such as heel cushioning, forefoot elasticity, and forefoot bending stiffness.These examples highlight the need for gender-specific and race-specific considerations in running shoe design.

Limitations
Our study has several limitations that should be acknowledged when interpreting the findings and considering their generalizability.Firstly, it is important to note that participants in our study did not wear the same shoes, which may have resulted in variations in wearing experiences and shoe preferences 58 .This heterogeneity in footwear selection could introduce bias and potentially influence participants' perceptions of shoe properties, thereby affecting the validity of our findings.Therefore, caution should be exercised when generalizing the results to populations where participants wear standardized shoes.
Secondly, our study recruited a relatively smaller number of elite players, which limits the generalizability of the findings to the elite athlete population 59,60 .Elite athletes often possess unique characteristics and preferences that differ from recreational runners, and their perceptions of shoe properties may vary significantly.Hence, the applicability of our results to elite-level marathon runners should be interpreted with caution.
Additionally, we acknowledge that the COVID-19 pandemic has had a significant impact on various aspects of society, including the field of sports and athletics.Unfortunately, our study did not assess data from the years 2020-2022, which coincided with the height of the pandemic.This represents a limitation in capturing the potential influence of the pandemic on Chinese marathon runners and their perceptions.

Conclusion
There were no gender differences between elite players' demand for running shoes, but significant gender differences were found between genders at other running levels.Both males and females agreed that "heel cushioning" was the most critical running shoe feature.Females pay more attention to the protection brought by shoes, while males pay attention to the sports performance of shoes.
In conclusion, our study underscores the importance of considering gender and distance factors when designing running shoes.The distinct characteristics demanded by male and female runners, along with the variations related to different running distances, emphasize the need for customization and optimization in the development of running footwear.We believe that our findings contribute valuable knowledge to the field and have practical implications for the running shoe industry.

Figure 1 .
Figure 1.Gender differences in shoe properties functional perception of first-level participants in the full marathon.Note: (A) Not important for running performance and prevent injuries, (B) Important for running performance, (C) Important for prevent injuries, (D) Important for both running performance and prevent injuries.*Indicates a significant difference, P < 0.05.

Figure 2 .
Figure 2. Gender differences in functional perception of shoe properties second-level participants in the full marathon.Note: (A) Not important for running performance and prevent injuries, (B) Important for running performance, (C) Important for prevent injuries, (D) Important for both running performance and prevent injuries.*Indicates a significant difference, P < 0.05.

Figure 3 .Figure 4 .
Figure 3. Gender differences in functional perception of shoe properties first-level participants in the half marathon.Note: (A) Not important for running performance and preventing injuries, (B) Important for running performance, (C) Important for preventing injuries, (D) Important for both running performance and preventing injuries.*Indicates a significant difference, P < 0.05.

Table 1 .
Characteristics of participants.

Table 2 .
Gender differences in full-marathon participants' perceptions of the importance of shoe properties (Mean ± SD). *Indicates a significant difference, P < 0.05.

Table 3 .
Gender differences in half-marathon participants' perceptions of the importance of shoe properties (Mean ± SD). *Indicates a significant difference, P < 0.05.