Biceps femoris and semitendinosus--teammates or competitors? New insights into hamstring injury mechanisms in male football players: a muscle functional MRI study.
BACKGROUND
The hamstring injury mechanism was assessed by investigating the exercise-related metabolic activity characteristics of the hamstring muscles using a muscle functional MRI (mfMRI) protocol.


METHODS
27 healthy male football players and 27 football players with a history of hamstring injuries (recovered and playing fully) underwent standardised mfMR Imaging. The mfMRI protocol consisted of a resting scan, a strenuous bilateral eccentric hamstring exercise and a postexercise scan. The exercise-related T2 increase or the signal intensity shift between both scans was used to detect differences in metabolic activation characteristics (1) between the different hamstring muscle bellies and (2) between the injury group and the control group.


RESULTS
A more symmetrical muscle recruitment pattern corresponding to a less economic hamstring muscle activation was demonstrated in the formerly injured group (p<0.05). The injured group also demonstrated a significantly lower strength endurance capacity during the eccentric hamstring exercise.


CONCLUSIONS
These findings suggest that the vulnerability of the hamstring muscles to football-related injury is related to the complexity and close coherence in the synergistic muscle recruitment of the biceps femoris and the semitendinosus. Discrete differences in neuromuscular coordination and activity distribution, with the biceps femoris partly having to compensate for the lack of endurance capacity of the semitendinosus, probably increase the hamstring injury risk.
Department of Rehabilitation Sciences and Physiotherapy Ghent, Ghent University, Ghent, Belgium.
Joke
http://orcid.org/0000-0001-6631-4334
J
Schuermans
Department of Rehabilitation Sciences and Physiotherapy Ghent, Ghent University, Ghent, Belgium.
Damien
D
Van Tiggelen
Department of Rehabilitation Sciences and Physiotherapy Ghent, Ghent University, Ghent, Belgium.
Lieven
L
Danneels
Department of Rehabilitation Sciences and Physiotherapy Ghent, Ghent University, Ghent, Belgium Department of Physiotherapy, Aspetar, Doha, Qatar.
Erik
E
Witvrouw
D000328:Adult; D000704:Analysis of Variance; D000886:Anthropometry; D001265:Athletic Injuries / Q000209:etiology / Q000503:physiopathology / Q000534:rehabilitation; D015444:Exercise / Q000502:physiology; D005081:Exercise Therapy / Q000379:methods; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009126:Muscle Relaxation / Q000502:physiology; D012916:Soccer / Q000293:injuries*; D013708:Tendon Injuries / Q000175:diagnosis* / Q000503:physiopathology / Q000534:rehabilitation; D013997:Time Factors; D055815:Young Adult
Eccentric; Football; Hamstring; Injury; MRI