The mean electrical axis of the heart, while undergoing certain minor transformations, was not significantly altered by exercise.
Proceedings of the Iowa Academy of Science
©1968 Iowa Academy of Science, Inc.
Collier, Wade L.
"Studies of the Mean Electrical Axis During and After Exercise,"
Proceedings of the Iowa Academy of Science, 75(1), 285-290.
Available at: https://scholarworks.uni.edu/pias/vol75/iss1/38