79% of Hamstring Injuries Involve Biceps Femoris: Here’s Why

Rapid movements with high eccentric demands of the posterior thigh are likely the main cause of hamstring injury in professional male athletes, according to a new study.

In the study, “Hamstring injury patterns in professional male football (soccer): a systematic video analysis of 52 cases,” the researchers using video analysis describe the injury inciting events of acute hamstring injuries in professional soccer players.

The findings were published online on December 7, 2021, in the British Journal of Sports Medicine.

For the analysis, the researchers examined video footage from four seasons, 2014 to 2019, of the two highest divisions in German male soccer. The main focus was on moderate and severe acute non-contact and indirect contact match hamstring injuries.

Two raters independently categorized inciting events to determine specific injury patterns and kinematics.

Overall, there were 52 cases of hamstring injuries identified. The pattern analysis revealed 25 sprint-related and 27 stretch-related hamstring injuries.

“All sprint-related hamstring injuries occurred during linear acceleration or high-speed running. Stretch-related hamstring injuries were connected with closed chain movements like braking or stopping with a lunging or landing action and open chain movements like kicking,” the researchers wrote.

In stretch-related injuries, they observe a change of movement that involved knee flexion to knee extension and a knee angle less than 45° at the assumed injury frame in all open and closed chain movements.

The biceps femoris was the most affected muscle, accounting for 79% of all included cases.

“Despite the variety of inciting events, rapid movements with high eccentric demands of the posterior thigh are likely the main hamstring injury mechanism. This study provides important data about how hamstring injuries occur in professional male football and supports the need for demand-specific multicomponent risk reduction programs,” the researchers wrote.

The study authors included Thomas Gronwald, Christian Klein, Tim Hoenig, Micha Pietzonka, Hendrik Bloch, Pascal Edouard, and Karsten Hollander of the Institute of Interdisciplinary Exercise Science and Sports Medicine, MSH Medical School in Hamburg, Germany.