Effects of potassium + magnesium aspartate on muscle metabolism and force development during short intensive static exercise.

Improvement of muscle performance by 20%-50% in man at a submaximal work load after administration of potassium and magnesium salts of aspartic acid (K + Mg Asp) has been reported in the literature. Administration of K + Mg Asp has been reported to affect force production and energy metabolism in short-term activities of electrical stimulated animal muscles. The present study examined the possible effects of K + Mg Asp on: energy metabolism and force production of electrically stimulated rat quadriceps muscle and endurance time of a submaximal static force of voluntary contracting human muscles. In rat muscles metabolic parameters such as ATP, phosphocreatine, lactate, and L-aspartate were not influenced by oral administration of K + Mg Asp. Force parameters of rat quadriceps muscles were not enhanced after administration of K + Mg Asp. In human volunteers neither the exerted force nor the endurance time increased after oral administration of K + Mg Asp. An effect of K + Mg Asp on muscle metabolism by stimulation of the purine nucleotide cycle was not found. Improvement of muscle performance by 20%-50%, as reported for long-term activity, was not observed for short-term intensive activity.