THE EFFECTS OF HANDGRIP AND RANGE OF MOTION VARIATIONS ON MUSCLE ACTIVITY IN DIFFERENT DELTOID EXERCISES

This study aimed to compare the effects of handgrip and range of motion (ROM) variations on muscle activity in different deltoid exercises. 14 resistance-trained men volunteered for 1RM and EMG testing with a load corresponding to 80% of 1RM. The subjects performed three different handgrips during Dumbell Front Raise (DFR), two different ROM variations for Dumbell Lateral Raise (DLR), and two different handgrips during Dumbell Rear Delt Raise (DRDR). Electromyogram (EMG) activity was measured in the anterior, medial, and posterior heads of deltoids. For the DFR exercise, the highest mean EMG activity was greater for the anterior deltoid, and the highest activity was observed in pronate grip (PG) con (51.57%). For the anterior deltoid EMG activity was significantly greater in PG con (51.57%) compared with hammer grip (HG) con (43.36%) (p˂0.05). HG ecc activity (40.36%) was significantly greater than PG ecc (36.4%) in posterior deltoid (p˂0.05). For the DLR exercise, the highest activity was observed in medial deltoid, and for limited ROM (LTR) (20.74%). LTR con activity (19.37%) was significantly greater than full ROM con (FLR) (16.88%) in the anterior head (p˂0.05). For the DRDR exercise, the mean activity was greater in medial deltoid, and HG con showed the highest activity (24.47%). The mean electromyography activity for the posterior deltoid was significantly greater in standard grip (STD) ecc compared with HG ecc (17.3%) (p˂0.05). In conclusion, for the heads of the deltoid muscle, the use of the different handgrip and ROM variations may increase neuromuscular activity.