The complexity of groin injury In search of the injury mechanism

Groin injury is the most frequent reported overuse injury in football and a plague for athletes, coaches and trainers because of the high risk for recurrence and chronicity. In this thesis we wondered why groin injury has such high risk for recurrence in Dutch female and male football players. We found that depending on frequency, duration and performance level, 39%-71% of previous groin injuries recurred during the next preseason, mostly recurring during maximal kicking. In our risk factor study we demonstrated that serious injury in the previous season (median 9 weeks timeloss) to locations other than the groin (ankle, knee, thigh and shoulder) were strong predictors (hazard ratio 5; BI 2-15) of timeloss groin injury during the next season. To understand the relationship of previous injury, groin injury and kicking, we examined the biomechanics of the football kick. It showed that from submaximal (70 km/u) to maximal kicking (100 km/u) the mobility of the lumbar spine and pelvis demonstrated the greatest relative increase. Also a full-body backswing was larger during maximal kicking. Both phenomena attribute to generation and transfer of energy to the kicking leg causing high ball precision and speed, avoiding extreme adductor work. Examination of football players with groin injury showed decreased mobility of pelvis and tension arc.
Previous injury may deteriorate kicking technique facilitating groin injury. By a manual stretch technique of the adductors most football players with adductor-related groin injury (82%) returned to sport within two weeks with improved kicking capacity.
For clinical practice, our research produced two reliable, sport specific assessment tests and an effective treatment technique for quick Return To Sport. Previous serious injury and analysis of the kicking technique earn attention in the treatment and prevention of groin injury.