Abstract: The present invention is directed to the treatment of muscular dysfunction or increasing muscle strength and/or decreasing muscle fatigue in a subject using a composition that includes a biguanide or a pharmaceutically acceptable salt thereof, e.g., at a low dosage.

Abstract: Described are assemblies for screening a compound for bioactivity, the assemblies comprising a tissue and a sensor. A change in a biological parameter is measured by the sensor, such that a change in a parameter occurring when the tissue is contacted with a candidate compound is detected by the sensor. Assemblies provided herein include single sensor/tissue assemblies and arrays of such assemblies, including plates comprising tissues in combination with one or more sensors. Also provided are methods of screening a compound using tissue/sensor tissue assemblies as described.