||The start of the concentric phase seemed to produce the greatest activation in previous studies, which seems to be appropriate, as the change in momentum from eccentric to concentric would create the greatest strength requirement, and therefore muscle activation. In this study, the bench press held true to that, peaking very early in the concentric phase, but the cable crossovers had data that seemed to be somewhat inverse of that data. It was the end, as opposed to the beginning, of the concentric phase that produced the greatest muscle activation. This would seem to accompany a greater range of motion following more closely to the orientation of muscle fibers in the sternocostal head of the pectoralis.|
This anatomical orientation in itself seems to offer some explain of the mechanical advantage in the activation of the sternocostal head of the pectoralis in the crossover compared to the bench press. Simply judging by the line of pull created from the origin to insertion of the sternocostal head, the cable crossovers would have a more direct following.
Another anatomical explanation incorporates the triceps brachii, which have been shown to have a large impact on the production of force in the bench press. Though the highest electrical activity occurs during narrow grip bench presses, and the least during wider presses, they still would seem to have a much higher involvement in the bench press than the cable crossover, as the bench press, regardless of grip width, still incorporates elbow extension.
Likewise, the anterior deltoid would seem to also have a higher involvement during the bench press than the cable crossover as it must perform at least a minor degree of flexion in the sagital plane, where this is not necessary in cable crossovers. This could create an impact on total electrical activity of the pectoralis major.
Though there is less validity in cross-comparing the upper chest data to the lower chest data, there is some indication that the lower chest is activated more heavily in both bench press and cable crossovers. This conclusion has been made in other studies strictly regarding the bench press, and is replicated by the data of this study for both bench press and cable crossovers. This particular data actually shows a greater distinction between activation of the lower and upper pectoralis in the cable crossovers than the bench press, such that the greatest EMG reading is the lower pectoralis in the cable crosses, and the smallest reading is that of the upper chest in the cable crossovers.
Though there are many limiting factors to extract conclusive statements regarding these two exercises, this study does give a strong indication in the distinction between activation of the sternocostal and clavicular heads of the pectoralis muscle among bench press and cable crossovers. This data is intended to be regarded as a pilot study giving reason to look into the subject in further detail.
If this study was to be broadened, standardization of form on the exercises could be monitored further through selecting participants who have greater coordination in the ability to properly perform the exercise. This could be accomplished by testing only those who are previously trained in both bench press and cable crossovers.