Regression Analysis Of Research Trendlines Based On Clinical Articles In Msse From 2009-2010 To 2023-2024

Research trendlines have been documented as a linear or curve one in some fields. However, no articles are found to analyze if the research trendline of clinical articles is a linear or curve one. The purpose of this study was to analyze research trendlines based on clinical articles published on Medicine & Science in Sports & Exercise (MSSE) from 2009-2010 to 2023-2024. All clinical articles published on MSSE from 2009-2010 to 2023-2024 were reviewed. Their yearly numbers were counted by two reviewers for an interrater reliability and were fitted with five types of regressions, exceptional, linear, logarithmic, polynomial, and power. The best fitted one with the highest R2 was selected. If the best fitted trendline has ascending and descending stages, those yearly numbers in each stage were fitted with five types of regressions. The best fitted one with the highest R2 was selected for a stage. A total of 631 clinical articles (M = 42.07/year) were identified. An interrater reliability coefficient of 90% was obtained. The best fitted equation from 2009-2010 to 2023-2024 was a polynomial equation, Y = -25.55 + 5.67X - 0.35X2, R2 = 0.47, F(2, 14) = 5.37, p = 0.02, showing a flatted hill-shape, in which an ascending stage from 2009-2010 to 2016-2017 and a descending stage from 2016-2017 to 2023-2024 were included. Since no significant differences of R2s among five types of regressions fitted in each stage were found, a linear regression equation was selected to fit the tradeline in each stage. In the stage from 2029-2010 to 2016-2017, the linear regression equation, Y = 29.89 + 2.69X, R2 = 0.69, F(1, 7) = 13.82, p = 0.01, was fitted, showing that the yearly number has increased at an increasing rate of 2.69 articles per year; while in the stage from 2016-2017 to 2023-2024, a linear regression equation, Y = 54.71 - 2.63X, R2 = 0.44, F(1, 7) = 4.76, p = 0.07, was obtained, indicating that the yearly number has decreased at a decreasing rate of 2.63 articles per year. These results documented that the clinical studies from 2009-2010 to 2023-2024 demonstrate a flatted hill-shape, not a linear line, in which the first stage from 2009-2010 to 2016-2017 has increased before 2017-2018, while the second stage from 2016-2017 to 2023-2024 has decreased since 2016-2017. It seems that there is a need for clinical researchers to increase clinical research activities.