Comparison of shoulder strength in males with and without myofascial trigger points in the upper trapezius

Clin Biomech (Bristol, Avon). 2017 Nov;49:134-138. doi: 10.1016/j.clinbiomech.2017.09.001. Epub 2017 Sep 6.


Background: This study was conducted in order to compare the strength of scapular elevator and shoulder abductor with and without restricted scapular elevation between male subjects with and without myofascial trigger points in the upper trapezius.

Methods: In total, 15 male subjects with myofascial trigger points, and 15age- and weight-matched male subjects without myofascial trigger points in the upper trapezius. Each subject was measured in the strength of maximum isometric scapular elevation and shoulder abduction with and without restricted scapular elevation. Maximum isometric contractions were measured using the Smart KEMA strength measurement system. Independent t-tests were used to compare shoulder strength values between the myofascial trigger points and non- myofascial trigger points groups.

Finding: The results showed that shoulder abductor strength in the group with myofascial trigger points (5.64kgf) was significantly lower than in the group without myofascial trigger points (11.96kgf) when scapular elevation was restricted (p<0.05). However, there was no significant difference in the strength of the scapular elevator or shoulder abductor between groups (p>0.05).

Interpretation: These findings suggest that decreased strength in the shoulder abductor with restricted scapular elevation should be considered in evaluating and treating individuals with myofascial trigger points of the upper trapezius.

Keywords: Biomechanics; Myofascial trigger point; Shoulder abductor strength; Synergic muscle; Upper trapezius.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Electromyography
  • Humans
  • Isometric Contraction / physiology*
  • Male
  • Myofascial Pain Syndromes / physiopathology*
  • Shoulder Joint / physiopathology*
  • Superficial Back Muscles / physiopathology*
  • Trigger Points / physiopathology*
  • Young Adult