Shoulder Muscle Activation Of Novice And Weight-trained Females During Push-ups On An Unstable Surface

Document Type

Article

Publication Date

6-1-2012

Publication Title

Medicine & Science in Sports & Exercise

DOI

10.1249/01.mss.0000417529.22755.ed

ISSN

1530-0315

Abstract

Performing closed kinetic chain exercise on an unstable surface increases the muscle stability demands. In contrast to the research conducted considering lower extremity and muscle activation during training on unstable surfaces, there is a lack of research on the upper extremity. Furthermore whether acute responses differ between weight-trained versus untrained subjects is unknown.

PURPOSE: To compare shoulder muscle activation of novice (untrained) and experienced weight lifters during three different push-up variations.

METHODS: Muscle activity of the dominant arm biceps brachii (BI), triceps (TR), upper trapezius (UT), anterior deltoid (AD), sternal (SPM) and clavicular (CPM) portions of the pectoralis major and the serratus anterior (SE) were measured by way of surface electromyography (EMG) in 12 novice 64.33±10.08kg, 1.69±0.07m, 23.0±2.8yrs) and 12 experienced (64.58±8.02kg, 1.69±0.04m, 22.6±1.7yrs) weight lifters. Subjects performed five repetitions of three push-up variations, stability discs under hands, stability discs under feet, no stability disc, in a random order. Average EMG amplitude during the concentric phase of each push up variation repetition was computed and averaged across the five trials. Separate group by push up variation analysis of variance was used for each muscle with statistical significance considered at P<.05.

RESULTS: With the exception of the BI, exercise had significant effects on muscle activity. Four muscles, SPM, CPM, AD and TR, demonstrated significantly higher activity during PUH and SPU compared to PUF. UT demonstrated significantly greater activity during PUH compared to SPU and PUF. SA demonstrated significantly greater activity during SPU compared to PUH. SPM, CPM, and TR, demonstrated group effects with the novice group eliciting significantly greater activity than the experienced lifters.

CONCLUSIONS: Performing push-ups with the hands on the discs did not increase muscle activity compared to standard push-ups. This suggests that PUH can be used to promote stabilizer activity without compromising prime mover activation. Perhaps explaining the reduction in activation for PUF compared to SPU was a change in center of mass position. Higher activation in novices is likely explained in differences in push-up execution.

Comments

Copyright © 2012 by the American College of Sports Medicine

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