Does verbal and tactile feedback change EMG activity in shoulder girdle and trunk muscles during plyometric exercise in overhead athletes with and without shoulder pain?

OBJECTIVES

To investigate if there is a difference in muscle activity for overhead athletes before and after an intervention with correction of both core and scapula compared to no intervention and is there a difference between overhead athletes with or without shoulder pain.

DESIGN

Controlled laboratory EMG study including intervention.

SETTING

University EMG laboratory.

PARTICIPANTS

Sixty overhead athletes, 30 with shoulder pain and 30 healthy controls were included performing plyometric rotational shoulder exercise.

MAIN OUTCOMES: Half of the participants received an intervention the other half were controls with no intervention. EMG muscle activity from 10 scapular, thoraco-humeral and trunk muscles were measured.

RESULTS

There were no significant differences in muscle activation levels between the groups with or without intervention. For the shoulder pain group, there were significant lower activity in Upper Trapezius when repeating the exercise. The shoulder pain group had significant higher activity in Pectoralis Major compared to the Healthy Control group.

CONCLUSIONS

Most differences were found between the pre- and post-test. Repetition of the exercise seems to be more important than verbal and tactile instructions. Comparing the shoulder pain group with the healthy controls confirms previous findings that, pain patients recruit muscles differently from healthy persons.