Comparison of Peak Force and Myoelectric Activity of the Anterior and Middle Deltoid at Three Shoulder Angles During Frontal, Diagonal, and Lateral Raise Exercises in Trained Men

The objective of the present study was to compare the peak force and myoelectric activity of the anterior (AD) and middle deltoid (MD) at three different shoulder joint angles during the frontal (FR), diagonal (DR), and lateral raise (LR) exercises in recreationally-trained men. Fifteen resistance-trained men (age: 27±5 years, height: 173±9 cm, total body mass: 81±10 kg) were assigned to this study. Three resistance exercises (FR, DR, and LR) were tested isometrically at three different shoulder joint angles (0°, 45°, and 90°). Peak force (PF) and myoelectric activity (iEMG) were measured for all exercises and shoulder joint angles. A two-way repeated-measures ANOVA (3x3) was used to test differences between exercises (FR, DR, and LR) and shoulder joint angles (0°, 45°, and 90°) for PF. A three-way repeated-measures ANOVA (2x3x3) was used to test differences between muscle groups (AD and MD), exercises (LR, DR, and FR), and shoulder joint angles (0°, 45°, and 90°) for iEMG. All RT exercises presented similar levels of force production and myoelectric activity (AD and MD) regardless of the specific plane of motion (p>0.05). However, the shoulder joint position affected the force production and AD activity without changes for MD.