However, a recent study by Chalmars et al (2014) found that the long head of biceps muscle tendon, which crosses the front of the shoulder, was in fact highly active during overhead activities of the shoulder. They theorise that the long head of biceps actually functions as an important shoulder stabiliser and humeral head depressor, assisting the rotator cuff in maintaining the precise balance of shoulder joint position essential for shoulder health.
Might be worth working on those guns after all !
Chalmers, P. N., Cip, J., Trombley, R., Cole, B. J., Wimmer, M. A., Romeo, A. A., & Verma, N. N. (2014). Glenohumeral function of the long head of the biceps muscle: an electromyographic analysis. Orthopaedic journal of sports medicine, 2(2), 2325967114523902.