Activation of the three deltoid muscle portions during common strengthening exercises: A systematic review

Background The three portions of the deltoid muscle (anterior, middle, and posterior) are primary movers of several strengthening exercises and their contribution to different exercises can be measured using surface electromyography. Purpose To systematically review studies that evaluated the activation of commonly used exercises and their variations. Methods A search was conducted in PubMed (MEDLINE), Web of Science, Scopus and SciELO. Thirty-three studies met the inclusion criteria, evaluating at least one deltoid portion during conventional isotonic exercises (minimum load: 60% of one-repetition maximum or body weight) and reporting normalized values. Similar exercises were grouped, averaged, and ranked according to the resulting activation. Individual exercise variations were also ranked. Results For anterior deltoid, horizontal adductions (inclined) and horizontal adductions (horizontal) generated the greatest activation, while the inclined dumbbell fly was the individual exercise with greatest activation; for middle deltoid, abductions and horizontal abductions presented the greatest activation, with lateral raises associated with internal rotation being the exercises producing greatest activation. For posterior deltoid, pull-ups generated greatest activation, with the standard pull-up and the inverted row with a suspension device requiring the greatest individual exercise activation. Conclusions These findings can be useful for coaches and practitioners when choosing the most appropriate exercise for strengthening programs.