The evaluation of upper body muscle activity during the performance of external chest compressions in simulated hypogravity

Rebecca G Krygiel; Abigail B Waye; Rafael Reimann Baptista; Gustavo Sandri Heidner; Lucas Rehnberg; Thais Russomano

doi:10.1016/j.lssr.2014.01.004

The evaluation of upper body muscle activity during the performance of external chest compressions in simulated hypogravity

Life Sci Space Res (Amst). 2014 Apr:1:60-6. doi: 10.1016/j.lssr.2014.01.004. Epub 2014 Feb 4.

Authors

Rebecca G Krygiel¹, Abigail B Waye¹, Rafael Reimann Baptista², Gustavo Sandri Heidner², Lucas Rehnberg³, Thais Russomano⁴

Affiliations

¹ Centre of Human and Aerospace Physiological Sciences, Kings College London, London, United Kingdom.
² John Ernsting Aerospace Physiology Lab, Microgravity Centre, PUCRS, Porto Alegre, Brazil.
³ Centre of Human and Aerospace Physiological Sciences, Kings College London, London, United Kingdom; John Ernsting Aerospace Physiology Lab, Microgravity Centre, PUCRS, Porto Alegre, Brazil. Electronic address: lukirehnberg@googlemail.com.
⁴ Centre of Human and Aerospace Physiological Sciences, Kings College London, London, United Kingdom; John Ernsting Aerospace Physiology Lab, Microgravity Centre, PUCRS, Porto Alegre, Brazil.

PMID: 26432590
DOI: 10.1016/j.lssr.2014.01.004

Abstract

Background: This original study evaluated the electromyograph (EMG) activity of four upper body muscles: triceps brachii, erector spinae, upper rectus abdominis, and pectoralis major, while external chest compressions (ECCs) were performed in simulated Martian hypogravity using a Body Suspension Device, counterweight system, and standard full body cardiopulmonary resuscitation (CPR) mannequin.

Method: 20 young, healthy male subjects were recruited. One hundred compressions divided into four sets, with roughly six seconds between each set to indicate 'ventilation', were performed within approximately a 1.5 minute protocol. Chest compression rate, depth and number were measured along with the subject's heart rate (HR) and rating of perceived exertion (RPE).

Results: All mean values were used in two-tailed t-tests using SPSS to compare +1 Gz values (control) versus simulated hypogravity values. The AHA (2005) compression standards were maintained in hypogravity. RPE and HR increased by 32% (p<0.001) and 44% (p=0.002), respectively, when ECCs were performed during Mars simulation, in comparison to +1 Gz. In hypogravity, the triceps brachii showed significantly less activity (p<0.001) when compared with the other three muscles studied. The comparison of all the other muscles showed no difference at +1 Gz or in hypogravity.

Conclusions: This study was among the first of its kind, however several limitations were faced which hopefully will not exist in future studies. Evaluation of a great number of muscles will allow space crews to focus on specific strengthening exercises within their current training regimes in case of a serious cardiac event in hypogravity.

Keywords: Cardiopulmonary resuscitation; Electromyography; Hypogravity.