An Electromyographic Analysis of Lateral Raise Variations and Frontal Raise in Competitive Bodybuilders

The present study examined the muscle activation in lateral raise with humerus rotated

externally (LR-external), neutrally (LR-neutral), internally (LR-internal), with flexed elbow (LR-flexed)

and frontal raise during both the concentric and eccentric phase. Ten competitive bodybuilders

performed the exercises. Normalized surface electromyographic root mean square (sEMG RMS)

was obtained from anterior, medial, and posterior deltoid, pectoralis major, upper trapezius, and triceps

brachii. During the concentric phase, anterior deltoid and posterior deltoid showed greater sEMG RMS in

frontal raise (eect size (ES)-range: 1.78/9.25)) and LR-internal (ES-range: 10.79/21.34), respectively,

vs. all other exercises. Medial deltoid showed greater sEMG RMS in LR-neutral than LR-external

(ES: 1.47 (95% confidence-interval—CI: 0.43/2.38)), frontal raise (ES: 10.28(95% CI: 6.67/13.01)),

and LR-flexed (ES: 6.41(95% CI: 4.04/8.23)). Pectoralis major showed greater sEMG RMS in frontal

raise vs. all other exercises (ES-range: 17.2/29.5), while upper trapezius (ES-range: 2.66/7.18) and

triceps brachii (ES-range: 0.41/3.31) showed greater sEMG RMS in LR-internal vs. all other exercises.

Similar recruitment patterns were found during the eccentric phase. When humerus rotates internally,

greater activation of posterior deltoid, triceps brachii, and upper trapezius occurs. Humerus external

rotation increases the activation of anterior and medial deltoid. Frontal raise mainly activates anterior

deltoid and pectoralis major. LR variations and frontal raise activate specifically shoulders muscles and

should be proposed accordingly.