Glenohumeral Internal Rotation Deficit (or GIRD for short) is defined as loss of internal rotation of the shoulder while positioned in 90 degrees of abduction. This is a commonly restricted motion in athletes that is important to address. In overhead athletes, loss of this motion puts the shoulder at risk for injury. In weightlifters (Olympic or CrossFitters) many of the movements performed require optimal internal rotation of the shoulder for proper execution. Without full internal rotation, the entire shoulder complex must compensate and will be put into a poor position for both performance and shoulder health.
Frequent treatments for GIRD include stretching the tissues of the posterior shoulder (commonly the sleeper stretch) and shoulder joint mobilizations (performed by the athlete or by a manual therapist). While these are often effective, they can take lots of time and consistency to produce results.
The easiest (and often immediate fix) I have found for GIRD has been repeated towel stretching. I have athletes perform 20 reps, getting the shoulder to end range with each rep and remeasure. During my latest mobility class at my local CrossFit, 5 out of 5 athletes saw significant improvements in IR following the repeated IR stretch.
Clinically, I often see baseball players routinely performing the sleeper stretch and soft tissue work to the posterior shoulder without making significant gains. This movement has on several occasions immediately restored full motion.