Effect of shoulder position on triceps brachii heads activity in dumbbell elbow extension exercises

Elbow extension exercises in different shoulder positions are selected to raise distinct effort levels among the triceps brachii heads. Because there are several triceps exercises, its choice is a big challenge on resistance training prescription. The present study aimed to compare the electromyographic signal of triceps brachii long and lateral heads among three different elbow ranges of motion (ROM) during two commonly prescribed elbow extension exercises: overhead dumbbell elbow extension (OD) and lying dumbbell elbow extension (LD).

The long and lateral heads electromyographic signals were acquired from 21 resistance-trained men. One to two maximal repetitions of each exercise was performed with a 40% load of a maximal voluntary isometric contraction test. The signals of concentric and eccentric phases were divided into three equal ROMs each (initial, middle, and final).

Eccentric phase elicited less muscular activity than concentric in both exercises. Concentric contraction presented the same pattern during OD (long and lateral heads) and LD (lateral head). Initial and middle intervals elicited higher muscle activity than final interval. This behavior was also present in the eccentric contraction (initial demanded less activity than middle and final during both exercises).

Since both exercises presented similar activation patterns, the prescription of OD and LD on the same training routine should be avoided.