Authors: Ci Song, Pei Qin

Department of Health Management, School of Public Health, Nanjing Medical University

Corresponding authors: Ci Song, PhD, Department of Health Management, School of Public Health, Nanjing Medical University, 101 Longmian Road, Jiangning District, Nanjing, Jiangsu 211166, P. R. China (songci@njmu.edu.cn; Researchgate: https://www.researchgate.net/profile/Ci-Song-14).

Why is this project important?

Physical activity and health have become significant topics in the field of sports medicine (1, 2). Since its inception in 1964, BJSM has developed into a leading journal in this discipline, with a wide-ranging influence. In celebration of the 60th anniversary of the journal, we reviewed the original research published from2000 to 2024 to explore trends in sports medicine research published in BJSM.

How did we go about this?

This review includes 2,065 original research articles published in the ORIGINAL RESEARCH section of the British Journal of Sports Medicine (BJSM) from January 2000 to December 2024. It is important to note that this project did not analyze review or systematic review articles published in BJSM which make up a large proportion of its scientific papers. Thus, articles employing meta-analysis as the primary method, as well practice summary from consensus statements, editorials and commentaries, and re-published articles due to corrections were excluded. Based on our objectives, we categorized these articles according to three dimensions: research topic, study design and sample size, and study population. Five graduate students independently reviewed the articles, with two senior researchers overseeing the categorization process and resolving any discrepancies.

1. Research Topics

The research topics were categorized into five major themes:

1) Health Benefits of Physical Activity: This category includes studies that investigate the benefits of physical activity on physical fitness, chronic disease incidence, and all-cause mortality. It also encompasses studies examining the role of social programs and policy interventions in promoting physical activity. Within this theme, we further classified how physical activity was assessed (e.g., total volume, intensity, type, or combinations) and how outcomes were evaluated, such as binary variables (e.g., presence/absence of disease, survival/mortality); continuous variables related to physical performance (e.g., muscle strength, total activity time); and continuous variables related to disease outcomes (e.g., blood glucose, lipid levels).

2) Sports Injuries: This theme includes research on surveillance, prevention protocols, and mechanisms of sports injuries or negative events (e.g., psychological distress, burnout, harassment and abuse), as well as the evaluation of new assessment methods for injuries. 

3) Sports Performance: Although sports performance in the narrow sense has not been a priority area for the journal in recent years, a cumulative total of over a hundred articles have been published on this theme in a board sense. Thus, studies examed the effects of various exposures or stimuli (e.g., heat environments, hormonal interventions) on athletic performance, without a specific purpose of sports injuries were encompassed within this theme.

4) Musculoskeletal Rehabilitation: This theme focuses on rehabilitation strategies, particularly for musculoskeletal injuries.

5) Others: Articles that did not fit into the above categories were classified as “other”.

2. Study Design and Sample Size

Following epidemiological methods, we categorized study designs into three major types: 

1) Descriptive Studies, which category includes cross-sectional studies and case series. 

2) Analytical Studies, which includes case-control and cohort studies. 

3) Experimental Studies: which refers to studies involving interventions, primarily randomized controlled trials (RCTs).

For descriptive and analytical studies, sample sizes were grouped as <1,000, 1,000-10,000, and >10,000. For experimental studies, due to typically smaller sample sizes, we classified them as <100, 100-500, and >500. This stratification helped assess whether studies are trending toward larger sample sizes in the era of big data.

3. Study Population

To understand the focus of sports medicine research, we categorized study populations into two groups:

1) Elite/Competitive Athletes and Professionals: Includes studies on athletes, including professional athletes and college, high school or academy athletes, as well as coaches, and team physicians, often conducted in competitive events or professional training settings.

2) General Population: Encompasses studies conducted in community settings in the general population.

After categorizing all articles, we performed an annual statistical analysis to summarize and describe trends over time.

What did we find?

The focus of BJSM’s original research publications has primarily been on sports injuries and performance, topics focus on sports injuries and incline towards sports performance have accounted for 60% and 13%, respectively (total number of research articles: 2,065) of the original research over the past 25 years (Figure 1a). Research in these classic areas is crucial for the safety of athletes, coaches, and medical teams in training and competitions. Notably, despite the reliance on athlete reports and medical records in most studies, technological advancements, such as video analysis and GPS tracking, have increasingly provided more objective and accurate methods of observation. Furthermore, large-scale population studies (sample size > 10,000) have increased since 2015 (Figure 1b), and by 2023-2024, such studies have made up over 15% of the research. This rise correlates with the establishment of electronic records, monitoring systems, and large cohort studies.

However, sports medicine should place more emphasis on the role of exercise in promoting health (3). This area is crucial for guiding the general population in engaging in proper physical activity, popularizing sports health culture, and improving physical fitness. According to the trend of BJSM’s original research, particularly since 2022, studies on the health effects of exercise have been steadily increasing, now accounting for over 15% of the total research (Figure 1a). These studies mainly focus on the improvement of chronic diseases such as cardiovascular disease and cancer through physical activity, as well as the role of policies in promoting public participation in physical activity. Despite this, research focused on the general population remains insufficient. Analyzing the composition of research subjects in the journal reveals that studies on elite/competitive athletes and professionals make up a larger proportion (1,179 articles, 57%), while research focused on the general public is less (886 articles, 43%, Figure 1c). Additionally, studies on under-represented or low-activity groups, such as pregnant women, children, economically disadvantaged populations, and patients with underlying conditions, are even less common.

Figure 1. (a) Proportion of research topics for original articles and annual publications in the topic of sports-related health benefits (2000-2024); (b) Proportion and annual publications of descriptive and analytic studies categorized by sample size (2000-2024); (c) Proportion and annual publications of original articles categorized by research population (2000-2024); (d) Proportion of original articles categorized by main exposures; (e) Proportion of original articles categorized by type of main outcome variables

Upon further breakdown of the studies on the health effects of exercise (251 articles, Figure 1d), we found that most research focuses on factors like total physical activity (e.g., minutes of exercise, MET values), exercise intensity, and type (accounting for 80%). These factors are often involved in exercise prescriptions, providing data evidence for determining the “optimal dose” of physical activity. However, the diversity of public exercise contexts may pose challenges in measuring and assessing the effects of the “optimal dose” (4, 5). For example, how do factors like exercise location, time, and environment modify the effects of physical activity? Are there interactions between exercise behaviors and other behavioral factors (e.g., diet, sleep, work environment) or environmental factors (e.g., air pollution)? These potential joint effects of factors have yet to receive sufficient attention.

We also examined the outcome measures used in studies of exercise health effects (251 articles, Figure 1e). These outcome indicators are widely distributed across different types of metrics: 36% focus on binary long-term outcomes (such as cancer, mortality, and cardiovascular diseases), 32% on conventional clinical indicators (such as blood sugar and cholesterol), and 28% on exercise-related indicators (such as muscle strength). However, there has been limited involvement of novel clinical phenotypes, such as imaging-based body composition or pulmonary function, which could deepen our understanding of the functional mechanisms of exercise in relation to long-term outcomes.

Take home messages

In conclusion, the past 25 years of publications in BJSM reflect the development of sports medicine and exercise health, but also highlight research gaps. First, while most research focuses on elite/competitive athletes, how to translate the experience of competitive sports into promoting public health remains a key question, aligned with the spirit of the Olympics. Second, there is still a lack of research on the interactions between exercise, the environment, and other behavioral factors, as well as the relationship between exercise preferences, different forms of exercise, and health. With the accumulation of more evidence, future studies should place greater emphasis on personalized exercise prescriptions, rather than just focusing on total physical activity. Lastly, the integration of sports medicine with other disciplines, such as bio-informatics and genetics, still requires further development.

Looking ahead, we call for sports medicine to integrate real-world research evidence, investigate the heterogeneity and determinants of exercise behavior effects in the general population, explore the role of exercise in sub-health and long-term outcomes, and enhance attention to vulnerable groups, ensuring fairness and inclusivity in promoting health through physical activity.

References

1 Ding D, Ramirez Varela A, Bauman AE, et al. Towards better evidence-informed global action: lessons learnt from the Lancet series and recent developments in physical activity and public health. Br J Sports Med. 2020;54(8):462-468.

2 Ramírez Varela A, Cruz GIN, Hallal P, et al. Global, regional, and national trends and patterns in physical activity research since 1950: a systematic review. Int J Behav Nutr Phys Act. 2021;18(1):5. 

3 Ding D, Chastin S, Salvo D, et al. Realigning the physical activity research agenda for population health, equity, and wellbeing. Lancet. 2024;404(10451):411-414.

4 Tremblay MS. Challenges in global surveillance of physical activity. Lancet Child Adolesc Health. 2020;4(1):2-3. 

5 The Lancet Regional Health-Western Pacific. Context matters: physical activity in the Western Pacific region. Lancet Reg Health West Pac. 2024;49:101190.