Open AccessCardiovascular responses to active and passive cycling movements
Author(s) -
A. C. L. Nobrega,
Jon W. Williamson,
D. B. Friedman,
Claudio Gil So Ares De Araújo,
Jerf Mitchell
Publication year - 1994
Publication title -
medicine and science in sports and exercise
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.703
H-Index - 224
eISSN - 1530-0315
pISSN - 0195-9131
DOI - 10.1249/00005768-199406000-00009
Subject(s) - heart rate , contractility , cardiology , stroke volume , medicine , cycling , rating of perceived exertion , cardiac output , venous return curve , hemodynamics , blood pressure , archaeology , history
Ten healthy subjects were evaluated at rest and at 5 min of unloaded active (AC) and passive (PC) cycling. Passive limb movements were accomplished using a tandem bicycle with a second rider performing the movements. We measured heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), oxygen uptake (VO2), rating of perceived exertion (RPE), and electrical activity (EMG) of lower limbs muscles. Values for stroke volume (SV) and peripheral vascular resistance (PVR) were calculated. EMG, RPE, and VO2 were higher during AC than during PC (P < 0.001). CO increased during both modes of cycling, but during AC it resulted from a HR acceleration (73 +/- 2 at rest to 82 +/- 2 beats.min-1 at 60 rpm; P < 0.001) with no change in SV whereas during PC, SV increased from rest (65 +/- 4 at rest to 71 +/- 3 ml at 60 rpm; P = 0.003) along with no change in HR. PVR remained constant during PC, but decreased by 13% during AC (P < 0.001) and MAP increased only during PC (93 +/- 2 at rest to 107 +/- 2 mm Hg at 60 rpm). These results supports the concept that central command determines the HR response to dynamic exercise. The increase in SV and consequently in MAP during PC was probably due to increased venous return and/or to muscle mechanoreceptor-evoked increased myocardial contractility.