HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 91/1/103    most recent expphysiol.2005.032052v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Nishiyasu, T. Articles by Kondo, N. Search for Related Content PubMed PubMed Citation Articles by Nishiyasu, T. Articles by Kondo, N. Related Collections Themed Issue papers Human, Environmental & Exercise

¹ Laboratory of Exercise Physiology, Institute of Health and Sport Sciences, University of Tsukuba 1-1-1, Tennodai, Tsukuba City, 305-8574, Japan ² School of Medicine³ Faculty of Education, Yamaguchi University, Japan ⁴ Faculty of Developmental Sciences, Kobe University, Japan

We examined the way in which the duration of rhythmic muscle compressions affects cardiovascular responses and muscle oxygenation at rest and during dynamic exercise. We measured the mean arterial pressure (MAP), heart rate (HR) and oxygenation of the vastus lateralis muscle (by near-infrared spectroscopy) in eight healthy male subjects at rest and during supine bicycle exercise (50 and 100 W at 60 r.p.m.) while applying pulsed muscle compressions at 1000 ms intervals. Compression pressure and durations were 150 mmHg and 300, 600, 900 and 1000 ms (1000 ms being static continuous compression), respectively. During exercise, the pulsed leg compression was synchronized to each thigh extensor muscle contraction. The observed changes in muscle oxygenation were dependent on compression duration (increased at 300 ms, no change at 600 ms and decreased at 900 or 1000 ms) and were different from those seen at rest (increases at < 1000 ms and decrease at 1000 ms). This suggests that the effects of external pulsed muscle compression may have a duration threshold below which muscle pumping counteracts the obstruction to flow caused by the compression, and that the threshold is set at a shorter compression duration during exercise than at rest. Although HR and MAP did not change during pulsed compression at rest, during exercise they both increased progressively as compression duration increased. Thus, while exercising, the increased MAP and HR seen during the compression could be due to the combination and interaction of mechanical effects and the muscle mechanoreflex and/or metaboreflex.

(Received 29 August 2005; accepted after revision 5 October 2005; first published online 6 October 2005)
Corresponding author T. Nishiyasu: Laboratory of Exercise Physiology, Institute of Health and Sport Sciences, University of Tsukuba 1-1-1, Tennodai, Tsukuba City, 305-8574, Japan. Email: nisiyasu{at}taiiku.tsukuba.ac.jp

This article has been cited by other articles:

				P. B Raven Neural Control of the Circulation during Exercise Themed Issue Exp Physiol, January 1, 2006; 91(1): 25 - 26. [Full Text] [PDF]