Cardiovascular responses to external compression of human calf muscle vary during graded metaboreflex stimulation.
This study investigated the cardiovascular response to a standard external muscle compression during concomitant muscle metaboreflex stimulation of varying intensity in human calf muscle. Eleven healthy male subjects (mean (s.d.) age, 26 (5.6) years; height, 177 (5) cm; weight, 74.3 (6.8) kg) were seated in an isometric dynamometer with the angle of the knee at 90 deg, and the angle of the ankle at 85 deg. After a 150-s rest period, subjects were asked to either perform isometric plantar flexion at 20, 30, 40, 50, 60, 70 or 80% of previously determined maximum isometric contractile force (MVC) for 90 s, or to sit at rest for this period. A thigh cuff maintained circulatory occlusion throughout the exercise period and for 180 s post exercise. After 60 s of post-exercise circulatory occlusion (PECO), a calf cuff was inflated to 300 mmHg for 60 s followed by a further 60 s of PECO alone after which the thigh cuff was deflated. During PECO the mean arterial pressure (MAP) increase from rest was dependent upon the preceding exercise intensity (P < 0.001). Compression elicited a further significant change in MAP, and the magnitude of this change from the PECO baseline was also dependent upon the preceding exercise intensity (P < 0.01). These results are compatible with activation of a metabolically sensitised population of mechanoreceptive afferents in human muscle during external compression.
Bell
Martin P D
MP
School of Sport and Exercise Science, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. mpb106@bham.ac.uk
White
Michael J
MJ
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D017704:Baroreflex / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D003250:Constriction; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000294:innervation / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D010812:Physical Stimulation / Q000379:methods*; D011312:Pressure; D012039:Regional Blood Flow / Q000502:physiology; D013848:Thigh / Q000502:physiology