Hypertrophy is defined as:

Hypertrophy specifically refers to the process in which there is an increase in cell size without any change in the number of cells. This is a physiological response typically seen in muscles as a result of resistance training or increased workload, where the existing muscle fibers grow larger to accommodate the demands placed on them.

In contrast, definitions that describe a decrease in cell size, non-proliferative increases in cell types, or excessive growth without abnormality do not capture the essence of hypertrophy. Rather, those descriptions pertain to different biological processes or conditions such as atrophy, metaplasia, or other forms of growth that can occur in tissues due to various stimuli or pathologies. Understanding hypertrophy is crucial, especially in athletic training, as it relates to how muscle growth can improve performance.