O ver the past century, understanding the mechanisms underlying muscle fatigue and weakness has been the focus of much investigation. However, the dominant theory in the field, that lactic acidosis causes muscle fatigue, is unlikely to tell the whole story. Recently, dysregulation of sarcoplasmic reticulum (SR) Ca²⁺ release has been associated with impaired muscle function induced by a wide range of stressors, from dystrophy to heart failure to muscle fatigue. Here, we address current understandings of the altered regulation of SR Ca²⁺ release during chronic stress, focusing on the role of the SR Ca²⁺ release channel known as the type 1 ryanodine receptor.