Mouse Fitness as Determined Through Treadmill Running and Walking.

Endurance testing simultaneously assesses a wide variety of physiological systems including the cardiovascular, respiratory, metabolic, and neuromuscular systems (Gabriel and Zierath, Cell Metab 25:1000-1011, 2017). Treadmill running is a noninvasive method to evaluate fitness capacity in a longitudinal or cross-sectional manner. High-intensity exercise tests can be used to determine peak physical capacity in mice. However, because aging is associated with a progressive loss of physical capacity the running protocols can be adapted and optimized for aged mice.