Functional Imaging of Human Skeletal Muscle During Movement: Implications for Recruitment, Metabolism and Circulation

Imaging is a powerful strategy for the visualization of anatomical and functional information (levels and patterns of activation, perfusion, circulation, and metabolism etc.) in human skeletal muscle. Recent innovations in scientific technology, several new techniques and methods have been developing that visualize the function of muscle regarding recruitment, perfusion, and/or metabolism in exercise. This review is focused on three novel imaging techniques; magnetic resonance imaging, positron emission tomography, and near infrared spectroscopic imaging. These noninvasive imaging techniques provide us crucial information about human muscle function in exercise. The information includes following the assignments; 1) training effects on muscle function, 2) differences in muscle function and metabolism between trained and untrained individuals, and 3) heterogeneity of activation perfusion and metabolism within a single muscle or muscle group. Recent research studies applying these imaging techniques to human muscles are discussed in detail in this review.