Consequences of trapezius relaxation on the distribution of shoulder muscle forces: an electromyographic study

Prospective study of the relationship between musculoskeletal and psychological complaints and electromyographic activity during isometric muscular contractions in a working population

“…This occurrence would require more "help" from synergistic muscles or from other structures of the musculoskeletal system to maintain work effort. Studies of motor control show that muscular forces are redistributed in certain situations and that trapezius muscular activity can be reduced while a static posture is maintained (30,31). Our findings that musculoskeletal complaints predict reduced muscular activity in the trapezius muscle during sustained submaximal work support the hypotheses of inhibited muscular activation or altered coordination in acute and chronic pain situations (12,13).…”

Altered Scapular Orientation During Arm Elevation in Patients With Insidious Onset Neck Pain and Whiplash-Associated Disorder

“…27,30,41 The contribution of the middle trapezius may also be important to reduce clavicle elevation, as it has been demonstrated that a voluntary reduction of the upper trapezius activity, when the arm is elevated, increases mainly the activity of the rhomboids, the middle trapezius, and the serratus anterior. 40 The reduced posterior tilt is considered to be associated with short overactive pectoralis minor. 41 However, increased activity in the levator scapulae and the rhomboid muscles 28 may explain the increased scapular posterior tilt observed in the IONP group (FiGurE 5).…”

The effect of work pace on workload, motor variability and fatigue during simulated light assembly work

“…Also, the more forward, 'engaged' upper body posture during the HWP reduced the external gravitational torque on the moving arms, leading to a smaller force required from the muscles to support the arms. Finally, load sharing between the muscles in the upper extremity may differ between the work paces, including a transfer of activity in the high pace condition to synergistic muscles not recorded by the surface EMG electrodes (Palmerud et al 1998).…”