Effects of grip width and angle on sEMG, joint kinematics and moments during pull-ups

Pull-ups are a popular exercise, but few studies have focused on quantifying the force and moments exerted on the body during performance. In particular, the impact of different modalities, particularly the grip width and angle, are not well-known. The aim of this study was to characterise the influence of grip width and angle on pull-up biomechanics. Twenty-one male participants performed six pull-ups under 10 different conditions (semi-randomised manner), three angles (0°, 15°, 30°) and four grip widths (shoulder width; 40%, 45% and 50% of the metacarpal span). The sEMG activity of the main muscles, whole-body kinematics and the force applied to the bar were recorded. Joint angles and shoulder moments were obtained using an OpenSim musculoskeletal model. The results showed that placing the hands in a wide position (i.e. 50%) and at a pronounced angle (i.e. 30°) increased the activations of the pectoralis major and the rectus abdominis (+14% and +15% of the maximal voluntary isometric contraction, MVIC). Using a 0° angle increased the activation of the infraspinatus, inferior trapezius and latissimus dorsi up to 60% MVIC. Lastly, our results highlighted that a wide hand position increased the shoulder net joint moment by 7% and should therefore be used with caution to limit stress on the joint.