On Left Biceps Activation...
Ok, If we’re super in love with the right triceps for sagittal Right BC inhibition, aren’t we also loving the left biceps (long head) for the same reason?
Let’s consider not the long head of the biceps alone but the short head as well.
The scapula on the R is positioned in a state such that the inferior angle is moving posteriorly away from the ribcage and the superior edge is moving anteriorly toward the ribcage. This is facilitated by pec minor activation and subsequent triceps inhibition. Also, though perhaps to a lesser degree, the R biceps may act, via the long head, but also and possibly more importantly so, the short head (due to its attachment to the coracoid) synergistically with the pec minor. And the end result can be biceps tendinitis. One mechanism for reduction of the biceps activity is via triceps activation. On an interesting side note I had a pt with right biceps pain and the first line of attack was to activate right subscapularis. This was suggested because I already had him on a triceps program and he was neutral. By engaging subscapularis I facilitated IR of the humerus which was now positioned in ER as a result of neutrality, which yielded prolonged inhibition of the subscapularis. Subscapularis activation created internal rotation and internal rotation alone is sufficient to inhibit biceps, because it is a lack of internal rotation (as a compensatory strategy to manage system extension) that results in the alliance of biceps with anterior deltoid and upper trapezius on that R side. This polyarticular chain of muscle which becomes a respiratory accessory muscle chain at this point can become so dominant that injury is an inevitable outcome if no intervention takes place.
On the L side the position of the scapula is opposite the R in many cases and subsequent activation of the L biceps may be necessary as a result of its positional disadvantage. Likewise, inhibition of subscap may be necessary if it has been acting as a compensatory IR muscle to counter ER positioning. To that end, we should also see a need for activation of teres minor and infraspinatus (following repositioning) on the L side as well. Doing so can improve compensatory demands of internal rotation of the humerus when in the R BC pattern. Compensatory internal rotation of the humerus could then possibly increase L pec major activity as it acts synergistically with subscap during compensatory L TR in the R BC pattern. The end result of this patterning could easily create the need for L pec inhibition as a mechanism for L biceps activation! Thus the mechanism for increasing biceps activity (as opposed to triceps on the R side) would be to improve rotation via reduction of the “alliance” of pec major and subscapularis.
One must understand that not everyone develops biceps tendinitis as a result of L AIC, R BC patterning however if it becomes the case then the above scenario are likely. -Michael Cantrell MPT, PRC