The effect of Delayed Onset of Muscle Soreness on trapezius activity

The aim of the study was to investigate the effect of Delayed Onset of Muscle Soreness (DOMS) on trapezius surface electromyographic (sEMG) activity during different controlled activation levels. The study sample included 12 right-handed females (age 20 to 24 years) with no record of recent symptoms or signs of neck or shoulder pain. Pressure pain thresholds (PPT) and sEMG were recorded bilaterally from the trapezius muscle. The experimental conditions included nominal rest, arm coordination movements and sustained shoulder flexion, before and after the introduction of DOMS. The recordings were executed on two consecutive days, i.e. recordings on day 1 were performed while the trapezius was ‘pain-free’ while recordings on day 2 were performed with DOMS present in the trapezius muscle. DOMS was induced after recordings on day 1 by intensive eccentric exercise of the left upper trapezius. The results of the PPT test demonstrated a significant lower pain threshold of the exercised upper left trapezius muscle at day 2. Except for an increased sEMG activity during the coordination test, the muscle activity of the painful left upper trapezius remained unchanged from day 1 to day 2. In conclusion, the findings of similar sEMG activity during the ‘pain-free- and ‘pain-afflicted state’ resulting in a non support of the pain adaptation model. Keywords: Pain adaptation model, DOMS, Trapeziu