Moderately elevated extracellular [K⁺] potentiates submaximal force and power in skeletal muscle via increased [Ca²⁺]_i during contractions

The extracellular K + concentration ([K + ] o ) increases during physical exercise. We here studied whether moderately elevated [K + ] o may increase force and power output during contractions at in vivo-like subtetanic frequencies and whether such potentiation was associated with increased cytosolic free Ca 2+ concentration ([Ca 2+ ] i ) during contractions. Isolated whole soleus and extensor digitorum longus (EDL) rat muscles were incubated at...