Age related changes in the Q angle of non-professional football players

Elena Escamilla-Martínez; Fátima Sánchez Martín; Javier Ramos-Ortega; Paula González-García; María-Dolores Cortés-Vega; Lourdes Mª Fernández-Seguín

doi:10.1016/j.heliyon.2023.e16781

Age related changes in the Q angle of non-professional football players

Heliyon. 2023 May 27;9(6):e16781. doi: 10.1016/j.heliyon.2023.e16781. eCollection 2023 Jun.

Authors

Elena Escamilla-Martínez¹, Fátima Sánchez Martín¹, Javier Ramos-Ortega², Paula González-García^{3

4}, María-Dolores Cortés-Vega³, Lourdes Mª Fernández-Seguín^{3

4}

Affiliations

¹ Nursering Department, University of Extremadura, Spain.
² Podiatry Department, University of Seville, Spain.
³ Physiotherapy Department, University of Seville, Spain.
⁴ Institute of Biomedicine of Seville (IBIS), Spain.

Abstract

Background: Football practice involves a great muscular demand, leading to the development of the lower limbs that, on occasions, can cause deviations from the normal anthropometric values. The quadriceps angle (Q angle) is a value often taken as a reference for the alignment of the lower limbs.

Objective: To observe the changes of the Q angle in young football players, because of muscular effort, analyzing the differences between four groups of different ages and to determine whether the playing position might influence these variations.

Methods: A cross sectional study was carried out with 104 male subjects divided into four groups according to age: under 8 years-old, 8-17 years-old, 17-21 years-old and over 21 years-old. A photograph was taken in standing position and the Q angle was plotted with KINOVEA® software. As for the reliability of the measurements, intraclass intra and interobserver coefficient were 0.958 and 0.860 respectively. The study was conducted in mid-season.

Results: Q angle value is greater in those under 8 years of age and decreases gradually and significantly (p < 0.005) until 17-21 years of age, where it stabilizes at values of 5.73° ± 2.78 for right Q angle and 5.88° ± 2.55 for left Q angle. Two way ANOVA demonstrated a significant group*position interaction for goalkeepers with a medium effect size in both angles (p < 0.001) with a medium effect (η² Right Q angle = 0.31; η² Left Q angle = 0.37). The values remain unchanged in subjects over 21 years of age (p > 0.005), except for goalkeepers, who suffered a difference in the evolution of the angle within their age category (p < 0.005) and with a high effect size with the other positions (value > 0.8) except forward (value < 0.5).

Conclusion: This study determines that the Q angle in football players decreases with growth, reaching values below 15° at the end of development. Playing positions only influence players over the age of 21, and the Q-angle of goalkeepers is greater than that of other players.

Keywords: Football player; Q angle.