The Global Research Status and Trends in Ice and Snow Sports Injuries from 1995 to 2022: A Bibliometric and Visualized Analysis

Objective: The aim of the present study is to focus on the most popular winter sports programs, and to investigate the global research status and trends in sports-related injuries. Methods: The Web of Science (WoS) Core Collection database was chosen as original data and used for extracting publications on ice and snow sports injuries on 18 February 2022. Articles published in English between 1995 to 2022 were selected for this study. Results: Finally, for the topic search, a sum of 1605 articles were extracted and used for further analysis. The country and journal ranked first—in terms of total number, total citations and the highest H-index of publications—were the USA and American Journal of Sports Medicine, respectively. The affiliation with the most cited publications was the Norwegian School of Sport Sciences. The most influential first author with the most citations (2537 times), the greatest average citations per article (65.05 times) and the highest H-index (26) was Bahr R. Articles were divided into five main clusters based on keyword analysis: injuries study, head and neck damage study, risk study, therapy study and epidemiology study. Studies related to epidemiology and brain damage in ice and snow sports will continue to be research hot topics. Conclusions: In conclusion, our study indicates that the ice and snow sports injuries research domain is more prevalent in North America and Europe. This study contributes to a comprehensive understanding of ice and snow sports injuries and provides hotspot directions.


Introduction
The Winter Olympics promote the leapfrog development of global ice and snow sports and the ice and snow industry, enriching the content of fitness sports and improving people's health. With the promotion and popularization of the Winter Olympic Games, ice and snow sports are becoming popular worldwide. However, because of its characteristics of high speed and difficult motions, practicing ice and snow sports is more likely to result in sports-related injuries [1,2]. The increase in the number of people participating in snow and ice sports will inevitably raise the incidence of sports injuries. Injuries associated with acute trauma in ice and snow sports primarily involve the head, spine and upper and lower extremities, and seriously affect the health and career of athletes [3][4][5]. In order to detect and count the sports injuries that occur in participating athletes and to further protect the health of athletes, the International Olympics Committee (IOC), in cooperation with National Olympic Committees (NOC) and International Sports Federations, initiated and developed the Olympic injury and illness surveillance system in 2008 [6,7]. However, at the same time, what needs to be monitored, the main current international concerns and how 2 of 13 to monitor scientifically still need to be researched and explored. Therefore, the present study aims to perform a bibliometric analysis of ice and snow sports injuries research.
A bibliometric study is used for the analysis of co-authorship, co-occurrence, bibliographic coupling and co-citation of previous publications by applying a range of mathematical and statistical methods to quantitatively and qualitatively analyze and measure articles and other forms of publications. Bibliometric studies are widely used in various medical research fields [8][9][10][11][12][13].
However, as far as we know, there have been no studies related to bibliometric and visualized analysis of winter sports-related injuries up until now. Hence, the aims of this study are to investigate the global research status and trends of winter sports through bibliometric methods, to gain a more comprehensive insight into the changes in research trends in different research hotspots (incidence, characteristics, mechanisms and risk factors, etc.) of winter sports injuries in recent decades, in order to scientifically understand and further mediate the risks of injury and improve safety, and to provide directional guidance and research ideas for further research on winter sports injuries.

Data Source and Search Protocol
The publicly available data of publications were extracted through a search in the Web of Science (WoS) Core Collection, which is considered the optimum database for conducting bibliometric quantitative evaluation analysis [14]. The publications included in this study were published from 1995 to 2022. To ensure the quantity and quality of the articles, we selected a number of sports that were most relevant to specific injuries and used topics to search on 18 February 2022. The publications data were determined by two researchers. The search protocols and terms were as follows: TS = (ice sports injur* OR snow sports injur* OR winter sports injur* OR skiing injur* OR skating injur* OR ice hockey injur* OR snowboard injur* OR sled injur*). The type of document was refined to articles. The top three WoS research orientations that were closely related to this study were selected: sport sciences, orthopedics and surgery. Articles published in English were selected for this study. The extracted information included: publication years, authors, affiliations, publication titles, countries/regions, number of articles, total citations, average citations per item, and H-index. The flow chart for article inclusion and exclusion is shown in the Supplementary Material.

Bibliometric and Visualized Analysis Methods
The publication years, total citations, average citations per item, H-index and other basic characteristics were obtained by using the intrinsic analysis function of WoS. The H-index was proposed by the American theoretical physicist Jorge E. Hirsch in 2005-defined as whether h of his or her Np papers have at least h citations each and the other (Np-h) papers have ≤h citations each-as a useful and valuable index to provide a quantitative assessment of the importance, significance and broad impact of a scientist's cumulative research contributions and outputs [15][16][17]. Compared with the total impact factor and total citations, the H-index aims to better describe the scientific productivity and influence of authors, affiliations, countries/regions or journals [16,17].
VOSviewer software 1.6.18 (Leiden University, Leiden, The Netherlands) was used for constructing and visualizing bibliometric networks based on co-authorship, co-occurrence, bibliographic coupling and co-citation relations [18][19][20]. VOSviewer provides a better understanding and easier interpretation of different terms and clusters through the construction of network visualization maps, overlay visualization maps and density visualization maps. Overlay visualizations can, for instance, be used to show developments over time. Density visualizations provide a quick overview of the main areas in a bibliometric network. The publications data extracted from WoS were imported into VOSviewer to analyze the number of articles, understand the prominent authors, affiliations, journals and countries/regions, mine the highly influential articles, understand the research frontiers and hotspots and explore the future research direction in this domain. The size of the nodes and the thickness of the connecting lines correlate with the importance of the type and unit of the analysis. Associations between authors, affiliations and countries/regions are visualized by weighted total link strength (TLS) lines.

Publication Output and Growth Trends
As of 18 February 2022, for the topic search, a sum of 1605 articles were extracted from WoS. Figure 1 shows the top fifteen countries/regions, affiliations, journals in number of articles, and the growth trends of publications over the past 28 years.
construction of network visualization maps, overlay visualization maps and density visualization maps. Overlay visualizations can, for instance, be used to show developments over time. Density visualizations provide a quick overview of the main areas in a bibliometric network. The publications data extracted from WoS were imported into VOSviewer to analyze the number of articles, understand the prominent authors, affiliations, journals and countries/regions, mine the highly influential articles, understand the research frontiers and hotspots and explore the future research direction in this domain. The size of the nodes and the thickness of the connecting lines correlate with the importance of the type and unit of the analysis. Associations between authors, affiliations and countries/regions are visualized by weighted total link strength (TLS) lines.

Publication Output and Growth Trends
As of 18 February 2022, for the topic search, a sum of 1605 articles were extracted from WoS. Figure 1 shows the top fifteen countries/regions, affiliations, journals in number of articles, and the growth trends of publications over the past 28 years.   Figure 1c. The author with the highest number of articles was Ruedl G (43), followed by Burtscher M with 40 articles and Bahr R with 39 articles (Figure 1d). Since 2010, the number of articles published in this field has been on an overall upward trend, peaking at 113 articles in 2021 ( Figure 1e). Figure 1g shows that the linear regression-predicted growth model equation based on historical data was Y = 2.649 × X − 5258, with X and Y representing the year and the predicted number of publications, which could help predict future trends. The number of publications is expected to reach 119 in 2030. A total of 1605 articles were written and published in English.

Publication Quality of Authors, Affiliations, Countries/Regions and Journals
The total citations, average citations per item and H-index of the top 15 countries/regions, affiliations, authors and journals with the most articles in the field of ice and snow sports injuries are illustrated in Tables

Co-Authorship Analysis
Co-authorship analysis was used to analyze authors' collaboration based on coauthored articles. Figure 3a showed a total of 837 authors were identified with a minimum of two articles. The author with the greatest TLS was Emery CA (126), followed by Bahr R with 97, Ruedl G with 96, Engebretsen L with 91 and Meeuwisse WH with 88. Figure 3b shows that a total of 525 affiliations were identified with a minimum of two articles. The affiliations with the greatest TLS over 100 were the University of Calgary (219), University of North Carolina (127), Harvard Medical School (113) and Norwegian School of Sport Sciences (108). Figure 3c shows that a total of 46 countries/regions were identified with a minimum of two articles. The top five countries/regions with the greatest TLS were as follows: Canada (212), the United States (194), Switzerland (134), England (120) and Germany (110).

Co-Occurrence Analysis
Co-occurrence analysis was used to reflect the strength of association between key words, and to determine the research hotspots, composition and paradigms of the disciplines or fields represented by these words, and to analyze the development process and structural evolution of the subject areas horizontally and vertically [21]. Figure 4a shows that a total of 233 identified keywords with a minimum of five occurrences were divided into five main clusters: injuries study (red color), head and neck damage study (blue color), risk study (green color), therapy study (yellow color) and epidemiology study (purple color). These categories are based on the keyword clustering algorithm generated within VOSviewer. The same color indicates that the articles are similar in terms of research content. The red cluster (123 items) includes keywords such as injuries, injury, biomechanics and performance, etc. The blue cluster (100 items) includes keywords such as ice hockey, concussion and sports, etc. In the green cluster (98 items), the most frequently appearing keywords are risk, skiing, children and snowboarding. In the yellow cluster (91 items), the most frequently appearing keywords are anterior cruciate ligament, knee and management. In the purple cluster (77 items), the most frequently appeareing keywords are epidemiology, prevention and players. An overlay visualization map was used to show the developments of keywords over time (Figure 4b). The overall trend gradually transited from injury and risk studies to therapy, epidemiology and brain damage studies over time.

Bibliographic Coupling Analysis
Bibliographic coupling analysis was conducted to reflect the relationship and similarity between two papers that cited a common third article [22,23]. Figure 5a shows that a total of 140 affiliations were identified with a minimum of five articles. The affiliations with the greatest TLS were the University of Calgary (56129), Norwegian School of Sport

Bibliographic Coupling Analysis
Bibliographic coupling analysis was conducted to reflect the relationship and similarity between two papers that cited a common third article [22,23]. Figure 5a shows that a total of 140 affiliations were identified with a minimum of five articles. The affiliations with the greatest TLS were the University of Calgary (56,129), Norwegian School of Sport Sciences (33,832), University of North Carolina (30,354), Mayo Clinic (23,939) and International Olympic Committee (21,417). Figure 5b shows that a total of 128 authors were identified with a minimum of five articles. The author with the greatest TLS was Engebretsen L (22,861), followed by Bahr R with 22,095, Steffen K with 96, Meeuwisse WH with 18,178 and Emery CA with 17,152. Figure 5c shows that a total of 65 journals were identified with a minimum of five articles. The journal with the greatest TLS was British Journal of Sports Medicine (25,

Co-Citation Analysis
Co-citation analysis was defined as the frequency with which two documents were cited together by other documents [24]. Figure 6a shows that a total of 256 journals were identified with a number of citations at least 20 times. The journal with the greatest TLS was American Journal of Sports Medicine (112796), followed by British Journal of Sports Medicine with 83647, Clinical Journal of Sport Medicine with 42745, Journal of Athletic Training with 30782 and Medicine and Science in Sports and Exercise with 29218. Figure  6b shows that a total of 260 authors were identified with a number of citations at least 20 times. The top five authors with the greatest TLS were as follows: Mccrory P (3722), Ruedl G (3592), Florenes TW (3366), Emery CA (3229) and Junge A (3061).

Co-Citation Analysis
Co-citation analysis was defined as the frequency with which two documents were cited together by other documents [24].

Discussion
We identified, through topic research, 1605 ice and snow sports injuries articles that were published in all journals in the WoS from 1995 and 2022. This bibliometric analysis of global research trends in the field of ice and snow sports injuries showed a steady increase in the number of publications over the past 28 years. These articles also covered a wide range of topics that appeal to all professionals. Through these articles, we can provide the necessary summary and overview of the changes in research trends in different research hotspots (incidence, characteristics, mechanisms and risk factors, etc.) of high-level events and winter sports injuries in recent decades.
Bibliometrics was introduced by Paul Otlet and has been popular among researchers in supporting quantitative analysis for understanding the literature and global research status and trends in a domain of interest [25,26]. In orthopedics, scientific methodology and approaches are important in fighting against occurrence and taking control over injury interventions. Within the aim of the study, a bibliometric and visualized analysis was conducted regarding ice and snow sports injuries.
Our study presented an objective and comprehensive overview of the trends and development in ice and snow sports injuries from 1995 to 2022. The annual number of articles related to ice and snow sports injuries has been increasing gradually over the past 28 years and will continue to increase in the next decade. It is speculated that the annual number of articles in this domain will continue to increase to 119 by 2030. The overlay visualization map is color-coded based on the year in which the keywords appear in the articles, and shows developments over time. From the explosion of keywords, we speculate that more and more researchers will focus on studies related to the epidemiology, brain injury and therapy regarding snow and ice sports injuries. Epidemiology-related studies can guide athletes and participants to be alert and avoid various potential injury factors during sports. Brain injuries have been attracting attention because of their greater potential for life-threatening injuries compared to other parts of the body. Therapy-related studies allow for the timely diagnosis and treatment of ice and snow sports injuries in combination with program characteristics and movement mechanisms in order to achieve optimal rehabilitation. These categories are scattered but each has its own focus. This prompts us to pay systematic attention to snow and ice sports injuries. For training guidance, it is important to focus on scientific protection and a multidisciplinary and integrated response plan.
At present, countries/regions, affiliations, authors and journals that mainly focus on snow and ice sports injury research are highest in number in developed Western countries. This is attributed to the long duration, wide audience and high level of winter sports programs in developed Western countries. According to bibliometric analysis, the Bahr R team, the Engebretsen L team, the Meeuwisse WH and Emery CA team, the Ruedl G and Burtscher M team and the Kerr ZY team still lead in this domain. University of Calgary, Norwegian School of Sport Sciences, University of North Carolina and University of Innsbruck still dominate the current direction of ice and snow sports injuries. American Journal of Sports Medicine, British Journal of Sports Medicine and Clinical Journal of Sport Medicine remain in an unassailable position for ice and snow sports injuries. The analysis results indicate that the journals and authors mentioned above are more deserving of attention. The above teams' studies in the field of ice and snow sports injuries are more likely to reflect the latest progress, and the breakthrough results and findings in this field are more likely to be reported in the above journals. The publication analysis shows that communication and cooperation between various international teams are increasing, and more exchanges and cooperation are needed to promote research in this area in the future.
Articles on ice and snow sports injuries in this study were extracted from the WoS Core Collection database. The bibliometric and visualized analyses are more objective and comprehensive compared to other studies and could help to understand research hotspots and explore future research directions. However, there are some limitations inherent in this study that must be considered. This study is limited to articles published after 1995, and only the top three WoS research orientations were selected in the study and analyzed. Therefore, partially important articles on ice and snow sports injuries were excluded. Additionally, we only selected a few sports that are most relevant to relevant injuries, so the accuracy of the analysis results is partially affected. Third, the bibliometric analysis is limited by database variation, i.e., PubMed, Scopus and Google Scholar are not included in our study [27]. Future research should include a more comprehensive orientation and a broader range of ice and snow sports. Finally, a phenomenon that also affects our findings is that some influential articles are cited a limited number of times [28].

Conclusions
This study analyzes publications regarding ice and snow sports injuries around the world by using bibliometric methods to reveal the current global research status and related trends. Since 2010, study on ice and snow sports injuries has been experiencing steady growth, mainly conducted in North America and Europe. The top three productive journals in the field of ice and snow sports injuries are American Journal of Sports Medicine, British Journal of Sports Medicine and Clinical Journal of Sport Medicine. Studies related to epidemiology, brain damage and therapy in ice and snow sports will continue to be research hot topics. Particularly, bibliometric and visualized studies focusing on ice and snow sports injuries can be a valuable tool for understanding the research frontiers and hotspots and exploring future research directions in this domain.
This study provides insight into how to enhance the awareness level of athletes, coaches and medical workers on ice and snow sports injuries, so as to scientifically and reasonably arrange training and skill actions to avoid injury risks and be alert to various potential injury factors during competition.
Supplementary Materials: The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/ijerph20042880/s1, Figure S1: The flow chart for article inclusion and exclusion.