Downhill running: a model of exercise hyperemia in the rat spinotrapezius muscle

• Published in: Journal of applied physiology (1985) Vol. 97; no. 3; pp. 1138 - 1142
• Main Authors: Kano, Yutaka, Padilla, Danielle, Hageman, K. Sue, Poole, David C, Musch, Timothy I
• Format: Journal Article
• Language: English
• Published: United States Am Physiological Soc 01.09.2004; American Physiological Society
• Subjects: Adaptation, Physiological; Animals; Blood Flow Velocity; Circulatory system; Exercise; Exercise Test; Forelimb - physiopathology; Hyperemia - physiopathology; Male; Models, Animal; Muscle, Skeletal - blood supply; Muscle, Skeletal - physiopathology; Muscular system; Physical Conditioning, Animal; Rats; Rats, Sprague-Dawley; Rodents; Running; Shoulder - blood supply; Shoulder - physiopathology
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00334.2004

Departments of Anatomy and Physiology and of Kinesiology, Kansas State University, Manhattan, Kansas 66506-5602 Submitted 25 March 2004 ; accepted in final form 30 April 2004 To utilize the rat spinotrapezius muscle as a model to investigate the microcirculatory consequences of exercise training, it is necessary to design an exercise protocol that recruits this muscle. There is evidence that the spinotrapezius is derecruited during standard treadmill exercise protocols performed on the uphill treadmill (i.e., 6° incline). This investigation tested the hypothesis that downhill running would effectively recruit the spinotrapezius muscle as assessed by the presence of an exercise hyperemia response. We used radioactive 15-µm microspheres to determine blood flows in the spinotrapezius and selected hindlimb muscles of female Sprague-Dawley rats at rest and during downhill (i.e., –14° incline; 331 ± 5 g body wt, n = 7) and level (i.e., 0° incline; 320 ± 11 g body wt, n = 5) running at 30 m/min. Both level and downhill exercise increased blood flow to all hindlimb muscles ( P < 0.01). However, in marked contrast to the absence of a hyperemic response to level running, blood flow to the spinotrapezius muscle increased from 26 ± 6 ml·min –1 ·100 g –1 at rest to 69 ± 8 ml·min –1 ·100 g –1 during downhill running ( P < 0.01). These findings indicate that downhill running represents an exercise paradigm that recruits the spinotrapezius muscle and thereby constitutes a tenable physiological model for investigating the adaptations induced by exercise training (i.e., the mechanisms of altered microcirculatory control by transmission light microscopy). skeletal muscle; blood flow; microvascular adaptation Address for reprint requests and other correspondence: T. I. Musch, Dept. of Anatomy/Physiology, College of Veterinary Medicine, 228 Coles Hall, 1600 Denison Ave., Manhattan, KS 66506-5802 (E-mail: musch{at}vet.ksu.edu ).