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

Abstract

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 (effect 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.

The Activation of Gluteal, Thigh, and Lower Back Muscles in Different Squat Variations Performed by Competitive Bodybuilders: Implications for Resistance Training

“…The participants were required to exert their maximum force against manual resistance. Each attempt lasted 5 s and three attempts were completed for each movement separated by 3 min of passive recovery [ 16 , 17 ]. The operators provided strong standardized verbal encouragements to push as hard as possible against the resistance exerted.…”

“…The surface electromyography (sEMG) electrodes were placed following the SENIAM recommendations [ 23 ]. To check for appropriate electrodes placement previous procedures were followed [ 17 ]. For example, if the electrode shifted over the innervation zone during part of the movement, the EMG amplitude was underestimated.…”

“…The same experienced operator placed the electrodes and checked the power-spectrum profile. This approach was shown to provide very high reliability in sEMG data [ 16 , 17 ].…”

“…The sEMG data were averaged excluding the first repetition of each set, to possibly have more consistent technique during the following repetitions. After, the sEMG RMS of each muscle during each exercise was normalized for its respective maximum voluntary isometric activation [ 16 , 17 , 27 ] and inserted into the data analysis.…”

“…Bodybuilders have a unique capacity to perform exercises with a profound consistency of their technique, and were recently used to investigate the differences in muscle activation when bench press [ 16 ] or shoulder raise variations [ 17 ] are performed. Additionally, examining the muscle activation during both the concentric and the descending phase may help practitioners to characterize the strength and the hypertrophic stimuli, given both the short-term [ 18 , 19 ] and long-term unique responses following traditional or eccentric-based exercise training [ 2 , 20 , 21 , 22 ].…”