Classic textbook depictions of mitochondria portray these organelles to be static bean-shaped structures. However the mitochondrial population is quite heterogeneous, and can form small individual organelles or extended reticula throughout muscle. This morphological plasticity is controlled by fission and opposing fusion events. Skeletal muscle mitochondrial morphology has been demonstrated to be altered under various disease conditions, including diabetes, denervation, as well as during development, aging, and exercise. This implies that mitochondrial fission and fusion machinery components are involved in regulating the architecture of the organelle during various states of muscle use and disuse. Furthermore, disruptions in either of these opposing processes have been demonstrated to result in diseases, suggesting that proper maintenance of mitochondrial morphology is critical for proper cell function.