Muscle plays a vital role in movement and metabolic regulation, establishing it as a cornerstone of overall health. Monitoring muscular parameters is critical for disease diagnosis, post-surgical recovery, and human–machine interface control. In recent decades, numerous technologies have emerged to monitor muscular biophysical and biochemical processes. The field has transitioned significantly from reliance on large, clinic-bound instrumentation to the development of miniaturized wearable and implantable systems capable of continuous real-time monitoring in everyday settings. This article presents a critical overview of recent advances, with a focus on material and device innovations in muscular monitoring. Starting with the fundamental characteristics of muscle tissue and the physiological origins of biosignals, the discussion subsequently shifts to recent developments in wearable and implantable bioelectronic systems tailored to monitor electrophysiological, biomechanical, and tissue oxygenation signals. Finally, current research challenges and outline emerging opportunities are highlighted in muscular monitoring. Owing to its interdisciplinary nature and growing societal demand for personalized healthcare, muscular monitoring is poised to catalyze transformative innovations in both clinical and consumer applications.