## 1 Introduction  
The crucial role of the scapula in shoulder stability and function [1; 2] has motived a large number of studies reporting data about scapula position and/or motion [2; 3; 4; 5; 6] and muscular activity [5; 7; 8; 9; 10; 11]. Apart from the known limitations of assessing scapulothoracic motion [2; 12; 13], reference values have been established for scapula position [3; 4; 6] and motion [2; 3; 4; 5; 6; 14]. Additionally, the roles of the scapular muscles during scapular motion and stability, as well as in shoulder function, have been stated [5]. The mentioned data were mainly reported during shoulder elevation, where the scapula is expected to perform the following: (a) upward rotation [2; 3; 4; 14] through the activity of the serratus anterior (SA) [7; 8; 9], upper (UT) [9; 10], lower (LT) [7; 8; 10], and middle trapezius (MT) [8; 15]; (b) lateral rotation [2; 6; 14] through the action of SA, MT [7; 8], and LT [7; 8; 10]; (c) posterior tilt [6], through SA [7; 8] and LT [10] activity; and (d) a slight elevation [16], through the action of levator scapulae (LS) [11] and UT [10; 11]. During the lowering phase, despite similarities with the scapulothoracic kinematics during shoulder elevation (1.1 to 3.3\({}^{\circ}\) of maximum difference), less scapular muscular activity was reported for UT, LT, and SA [14]. This difference seems to be related to the type of contraction required, the gravity effect [14], or the action of the antagonist muscles [8; 10]. Scapulothoracic motion and muscular changes were described for shoulder pain conditions. These adaptations are generally reported as a reduction in the expected scapular movements [2; 6; 14; 17; 18] (except for upward rotation in adhesive capsulitis [2; 19]) and as a reduction in muscular activity of the LT, MT, and SA [8; 14; 20; 21] together with an increased activation level of LS, pectoralis minor (Pm) [8; 22; 23], and UT [19; 20; 23]. Also, beyond its relevance for shoulder function, the scapula serves as the link between the upper limb and the trunk [14; 24], with the primary purpose of maximizing the available degrees of freedom to facilitate the hand's interaction during its activities [13; 25]. Given this fact, it is understandable that one of the major complaints of subjects with shoulder pain is related to its impact on daily activities [26; 27]. Therefore, considering functional activities with different degrees of freedom during the patients' assessment could provide new information for rehabilitation planning. Scapula outcome data have already been presented for some daily activities, primarily in healthy subjects [26; 28; 29; 30], but few studies have included participants with shoulder pain [26; 30]. The use of different tasks across studies seems to be related to the lack of a systematic protocol for upper limb assessment [13], which could limit repeatability [31] and comparison with other studies. However, since the movements of the upper limb could vary according to each task's purpose [32], studying other daily activities would complement the available knowledge. In particular, studying the drinking task, a common daily activity task associated with basic shoulder movements [33], could not only increase knowledge about a basic daily activity task [33] but also facilitate comparison with other studies. The drinking task has already been considered in the study of other populations [13; 32; 34; 35] and includes a phase, the reaching phase, reported as reliable to assess the upper limb motor performance in subjects with shoulder pain [36]. Despite all the aforementioned facts, discrepancies have arisen during the characterization of subjects with shoulder pain. For instance, there are conflicting findings regarding the activity level of scapular muscles, such as increased activation [37; 38] or no changes [26; 37] of the LT or increased SA [30; 39].