Regression Analysis of Research Trendlines for Clinical Articles Published on Medicine & Science in Sports & Exercise between 2009–10 and 2023–24

The purpose of this study was to analyze trendlines based on clinical articles published on <i>Medicine & Science in Sports & Exercise</i> (MSSE). Clinical articles published on MSSE from 2009-10 to 2023-24 were reviewed. The yearly numbers of these articles were counted by two reviewers for an interrater reliability and fitted with five types of regression equations. The best one fitted with the highest R² was selected to describe a trendline. If it has ascending and descending stages, each stage was fitted in a linear regression equation. A total of 631 clinical research articles (M = 42.07/per year) were identified. An interrater reliability coefficient of 90% was obtained. The best fitted equation was a quadratic polynomial equation, Y = -25.55 + 5.67X - 0.35X2, R² = 0.47, F(2, 12) = 5.37, p = 0.02, showing a flatted hill-shape, including an ascending stage from 2009-10 to 2016-17 and a descending stage from 2016-17 to 2023-24. In the stage from 2029-10 to 2016-17, the linear regression equation, Y = 29.89 + 2.69X, R² = 0.69, F(1, 7) = 13.82, p = 0.01, was fitted, noting that the yearly number of clinical articles has increased with a rate of 2.69 articles a year. In the stage from 2016-17 to 2023-24, 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 number of clinical articles has decreased with a rate of 2.63 articles per year. These results documented that the clinical studies from 2009-10 to 2023-24 demonstrate a flatted hill-shape trendline, in which the first stage from 2009-10 to 2016-17 has increased, while the second stage from 2016-17 to 2023-24 has decreased. It seems that currently, there is a need for clinical researchers to increase clinical research activities.