Muscles Recruitment Pattern in People with and Without Active Upper Trapezius Myofascial Trigger Points in the Standing Posture

Background: Myofascial trigger points are known as the main reasons for the neck pain. Myofascial trigger points may change the coordination of cervical muscles and cause impaired proprioception. Objectives: The aim of this study was to investigate the onset of shoulder and cervical muscles activity and muscles recruitment pattern in patients with an active myofascial trigger point in the upper trapezius. Methods: 15 patient subjects (aged 26.802.67 years) with one activemyofascial trigger point in the upper trapezius and 15 control subjects (aged 27.733.43 years) participated in this study. The subjects flexed their arms in response to a sound stimulus. The onset time of anterior deltoid was chosen as the initial point in showing the onset time of cervical paraspinal, lumbar paraspinal, upper trapezius, sternocleidomastoid, and medial head of gastrocnemius muscles. Results: The patient group represented a delay in the onset of muscles activity and altered muscle recruitment pattern compared to the control subjects (P < 0.001). However, the sternocleidomastoid muscle showed no delay in this group (P = 0.67). Conclusions: These results showed latency in the onset of muscles activity and altered muscles recruitment patterns. The altered muscles recruitment pattern may lead to changes in motor control strategies and poor control of movement. Finally, these changes can cause a poor control of movement and increase the possibility of damage to the shoulder and cervical muscles in patients with an active myofascial trigger point in the upper trapezius.