Muscle Architecture, Morphology, and Mechanical and Functional Properties of Biceps Femoris Long Head in Professional Soccer Players with a Prior Healed Injured Hamstring
Authors: Francisco Javier Nunez 1, Ramona Ritzmann 2, Fernando Hernandez-Abad 3, Juan Carlos Martinez 4, Luis Suarez-Arrones 1, 5
- Department of Sport Sciences, Universidad Pablo de Olavide, 41013 Sevilla, Spain
- Department of Sports and Sport Science, University of Freiburg, 79106 Freiburg, Germany
- Department of Sport Sciences, European University of the Canary Islands, 38300 Tenerife, Spain
- Medical Department, Tottenham Hotspur FC, London N15 4RU, UK
- Performance Departament, FC Lugano, 6900 Lugano, Switzerland
Journal: Journal of Clinical Medicine - December 2022, Volume 11, Issue 23, Article no. 7222 (DOI: 10.3390/jcm11237222)
Objective: The aim of the present study was to compare the fascicle length, pennation angle, muscle thickness and stiffness of the biceps femoris long head, and eccentric hamstring strength between injured dominant limbs, injured non-dominant limbs, uninjured dominant limbs and uninjured non-dominant legs in previously injured players, and between dominant and non-dominant legs in uninjured elite soccer players.
Materials and Methods: Twenty elite soccer players participated in this study. Ultrasound imaging and MyotonPRO were used to determine the morphological and mechanical properties of the biceps femoris long head. Isokinetic and Nordic hamstring exercises were used to assess eccentric hamstring strength.
Results: Previously injured players showed substantially lower fascicle length and muscle thickness, and significantly higher biceps femoris long head stiffness than uninjured players, without differences between limbs.
Conclusion: The morphological and mechanical properties of elite soccer players with hamstring injury history were different from those in uninjured players. The lack of differences between limbs showed that these values are characteristics of individual players that must be considered in the design of programs to prevent BFlh injury.
Keywords: hamstring injury, fascicle length, pennation angle, muscle thickness, Nordic hamstring exercise, isokinetic, football
Elite soccer players with previous HSI showed lower Fl and higher proximal stiffness in the BFlh in both the injured and non-injured legs than players without previous hamstring injuries. However, there were no statistical differences in muscle architecture, stiffness, NHE or isokinetic eccentric force between prior strained legs and uninjured legs in the injured players. This absence of differences in morphological and mechanical properties between limbs in the cohort with a history of HIS indicates the presence of a particular characteristic which would be considered in the design of future investigations and prevention programs.