D-23 Free Communication/Poster - Pulmonary: MAY 31, 2007 1:00 PM - 6:00 PM ROOM: Hall E
Previous studies have presented evidence that both support and refute the assertion that the serratus anterior (SA) is an accessory muscle in ventilation.
PURPOSE: To observe the muscle activation and tissue oxygen saturation (StO2) of the SA during graded upright cycling.
METHODS: Eight healthy volunteers (24.4 ± 1.4 years) completed a graded exercise test to volitional exhaustion on an electromagnetic ally braked cycle ergometer. The subjects' arms were folded and relaxed at the abdomen to minimize artifact resulting from scapular protraction, abduction, etc. Integrated electromyographic (iEMG) data were collected via Ag/AgCl bi-polar surface electrodes, placed on the lower fibers of the right serratus anterior as described by Cram et al. 1998. Manual muscle testing was completed via a push-up test to ensure accurate placement and signal conduction at the SA electrodes. Tissue oxygen saturation was examined using near infrared tissue spectroscopy (NIRS), with the infrared probe placed over the left SA. Oxygen consumption (VO2) and minute ventilation (VE) were monitored throughout exercise via breath-by-breath measurement. Repeated measures ANOVA were used to identify differences throughout the exercise bout.
RESULTS: No significant differences were observed throughout the graded exercise test for either iEMG or StO2 (P > 0.05).
CONCLUSIONS: Although the recruitment of the SA has been shown to aid in ventilation in various postures and disease states, the data suggested that the SA is not recruited for ventilation in healthy individuals during graded upright cycling.