Purpose: In many swimmers, the levator scapule is extremely tight from frequent arm stroking. Self myofascial releases (SMR) are likely to enhance range of motion of muscles, without decreasing muscular strength (MacDonald 2013).
Directions: Place a tennis ball or baseball in between the shoulder blade and the spine. Next, lie on your back with your knees bent, then roll slightly over this area, looking for the area of most tenderness. Stay on this area for 2 - 3 minutes and relax. For more about SMR read here: http://www.swimmingscience.net/2013/08/self-myofascial-release-should-replace.html and if you are looking for a comprehensive shoulder injury prevention program, consider the Swimmer's Shoulder System: http://www.corswimmershoulder.com/
Macdonald G, Penney M, Mullaley M, Cuconato A, Drake C, Behm DG, Button DC. An Acute Bout of Self Myofascial Release Increases Range of Motion Without a Subsequent Decrease in Muscle Activation or Force. J Strength Cond Res. 2012 May 10.