Vibration as an adjunct to exercise: its impact on shoulder muscle activation.

Author: Grant MJ1, Hawkes DH1,2, McMahon J2, Horsley I3, Khaiyat OA4
Affiliation: <sup>1</sup>Trauma and Orthopaedic Surgery, North West (Mersey) Deanery, Liverpool, UK. <sup>2</sup>School of Health Sciences, Liverpool Hope University, Liverpool, UK. <sup>3</sup>England Institute for Sport, Sports City, Manchester, UK. <sup>4</sup>School of Health Sciences, Liverpool Hope University, Liverpool, UK.
Conference/Journal: Eur J Appl Physiol.
Date published: 2019 May 31
Other: Special Notes: doi: 10.1007/s00421-019-04168-9. [Epub ahead of print] , Word Count: 263

PURPOSE: There is an interest within elite sport in understanding the impact of a vibrating platform as an adjunct to exercise in the training and rehabilitation of throwing athletes. However, there has been no comprehensive evaluation of its impact on the rotator cuff muscles or its effect on the timing of shoulder muscle recruitment more globally.

METHODS: Twenty healthy participants were recruited with EMG recorded from 15 shoulder girdle muscles. Isometric shoulder flexion at 25% maximal voluntary contraction was performed in three testing scenarios [no vibration; whole body vibration (WBV); and arm vibration (AV)]. A press up and triceps dips with and without vibration were also performed. Muscular recruitment was assessed pre- and post-vibration exposure as participants initiated forward flexion.

RESULTS: Activation of the anterior deltoid (p = 0.002), serratus anterior (p = 0.004), and rotator cuff muscles (p = 0.004-0.022) occurred significantly earlier following exposure to vibration. Significantly greater activation was seen in the anterior, middle and posterior deltoid, upper, middle and lower trapezius, serratus anterior, teres major, latissimus dorsi, supraspinatus, and infraspinatus when the isometric contraction was performed with either WBV and/or AV (p =  < 0.001-0.040). Similarly, increased activation was also demonstrated during the press up and triceps dips when performed with vibration.

CONCLUSION: The use of vibration as an adjunct to exercise provokes a near global increase in shoulder muscle activation level. Furthermore, exposure to vibration alters muscular recruitment improving readiness for movement. This has potential implications within elite sport for both training and game preparation; however, further longitudinal work is required.

KEYWORDS: EMG; Muscle activity; Muscle recruitment; Shoulder; Vibration

PMID: 31152231 DOI: 10.1007/s00421-019-04168-9