Relationship of brachial artery blood flow rate and muscle activity in the anterior flexor compartment of the arm: A test of asymmetry

Abstract

During strenuous activity, the human body must provide an adequate supply of oxygen to active muscles. Apart from a general upswing of blood flow to the muscles moderated by the sympathetic nervous system, the body appears to have a mechanism for directing blood flow to the specific acting muscles. This quantitative study documents blood flow rate (BFR) to muscles in need of oxygen by employing a mixed sex sample (n=20) of individuals between the ages of 22 to 25. Subjects performed a preset number of biceps curls (flexing the elbow against resistance) with one arm only. Left‐handed and right‐handed curls were split evenly among the participants. Increases in BFR were measured through ultrasound of the brachial artery just proximal to the elbow. Results showed a general increase in BFR in both arms with a substantially higher percent increase in the weight‐bearing arm. The average percent increase of BFR in the weight‐bearing arm was 130.5% with a standard deviation (sd) of 31.4% and a standard error (se) of 9.9%. The average percent increase of BFR of the non‐weight bearing arm was 47.1% (sd=53.4%, se=16.9%). These preliminary findings suggest an asymmetrical blood delivery increase favoring the active muscles. BFR increases are likely influenced by local muscle activity in a dynamic functional relationship.