The knowledge of the electromyographic activity produced during shoulder exercises can help in determining its clinical applicability. The purpose of this study was to assess the influence of the load direction and the extremity condition on the electrical activity of the shoulder girdle and upper limb muscles during exercises with fixed distal extremity and external axial load (FEAL) and mobile extremity with rotational external load (MERL). Twenty 23.2 ± 0.9 years old female sedentary volunteers were selected. The triceps brachii, biceps brachii, major pectoral, trapezium and deltoid muscles were assessed. The surface electromyography was recorded during two FEAL and two MERL exercises using 100% of the previously established maximal resistance. The RMS values normalized by the maximal voluntary contraction were compared by a mixed effect model with 5% significance level. In these experimental conditions, the results found in the present study have shown that similar exercises classified by extremity condition and load direction applied on the upper limbs promote similar levels of the electromyographic activity only in part of the assessed muscles. These findings discuss the ability of the classification system used in this study to predict the type of the muscular response expected during different tasks with the same classification.
Electromyography; Upper limbs; Shoulder; Exercises