This injury is primarily caused by force being applied during repeated arm abduction movements. In swimming for example this translates to the athlete using an excessively wide arm pull that results in medial rotation of the humerus as force is applied during the pull phase of the arm-stroke. This action results in the long head of the biceps tendon rubbing against the lateral side of the bicepital groove causing frictional stress on the tendon, abrading, inflammation and pain.
Poor technique in conjunction with repetitive action is the primary cause.
Arm in an adducted position elbow extension with shoulder hyperextension to gently stretch biceps tendon.
Very important as repeated incorrect technique will only result in re-occurrence of the injury despite repeated treatment.