|
|
||||||||
Research Reports |
JE Sherry, PT, MS, is a faculty associate, Physical Therapy Program, Department of Surgery, University of Wisconsin-Madison. She is also a staff physical therapist at the UW-Research Park Spine Physical Therapy Clinic, University of Wisconsin Hospitals and Clinics.
BJ Morgan, PT, PhD, is Associate Professor, Physical Therapy Program, Department of Surgery, University of Wisconsin-Madison
KM Oehrlein and KS Hegge were physical therapist students at the University of Wisconsin-Madison at the time this research was conducted
Address all correspondence to Ms Sherry at 4176 Medical Sciences Center, 1300 University Ave, Madison, WI 53706-1532 (USA) (sherry{at}surgery.wisc.edu)
Background and Purpose. Based on changes in skin temperature alone, some authors have proposed that postganglionic sympathetic vasoconstrictor fibers can be stimulated transcutaneously. Our goal was to determine the effects of low-frequency (2 bursts per second), burst-mode transcutaneous electrical nerve stimulation (TENS) on calf vascular resistance, a more direct marker of sympathetic vasoconstrictor outflow than skin temperature, in subjects with no known pathology. Subjects. Fourteen women and 6 men (mean age=31 years, SD=13, range=1858) participated in this study. Methods. Calf blood flow, arterial pressure, and skin temperature were measured while TENS was applied over the common peroneal and tibial nerves. Results. Blood flow immediately following stimulation was not affected by TENS applied just under or just above the threshold for muscle contraction. Transcutaneous electrical nerve stimulation applied at 25% above the motor threshold caused a transient increase in calf blood flow. Regardless of stimulation intensity, TENS had no effect on arterial pressure; therefore, calf vascular resistance decreased only during the trial that was 25% above the motor threshold. Regardless of stimulation intensity, TENS failed to alter dorsal or plantar skin temperature. Discussion and Conclusion. These results demonstrate that the effects of TENS on circulation depend on stimulation intensity. When the intensity was sufficient to cause a moderate muscle contraction, a transient, local increase in blood flow occurred. Cooling of the dorsal and plantar skin occurred in both the stimulated and control legs, most likely because skin temperature acclimatized to ambient room temperature, rather than because of any effect of TENS on circulation. The data, therefore, call into question the idea that postganglionic sympathetic efferent fibers are stimulated when TENS is applied at clinically relevant intensities to people without symptoms of cardiovascular or neuromuscular pathology.
Key Words: Electrical stimulation Physical therapy Regional blood flow Sympathetic nervous system Vascular resistance
![]()
CiteULike
Complore
Connotea
Del.icio.us
Digg
Reddit
Technorati What's this?
This article has been cited by other articles:
![]() |
M. L Sandberg, M. K Sandberg, and J. Dahl Blood Flow Changes in the Trapezius Muscle and Overlying Skin Following Transcutaneous Electrical Nerve Stimulation Physical Therapy, August 1, 2007; 87(8): 1047 - 1055. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |