The Effect of Olive Leaf Extract Supplementation on Training-induced Skeletal Muscle Functional and Molecular Adaptations in Healthy Volunteers

Maximal exercise capacity (VO2peak) predicts cardiovascular risk and all-cause mortality. Regular moderate to vigorous physical activity, a key determinant of VO2peak, is essential for an optimal health status of the general population. Thus, strategies that accentuate the health benefits of exercise may have considerable therapeutic benefits. Skeletal muscle Ca2+ handling is a primary determinant of exercise capacity. The regulation of skeletal muscle contraction by Ca2+ is coupled to mitochondrial energy production through a mechanism involving transport across the inner mitochondrial membrane by the mitochondrial Ca2+ uniporter (MCU). Ca2+ entry in the mitochondrial matrix controls Ca2+ -sensitive enzymes, including pyruvate dehydrogenase (PDH) activity, a rate-limiting enzyme for glycolysis. Olive leaf extract (OLE) contains ~40% of the natural polyphenol oleuropein and is a potent activator of MCU in skeletal muscle with anti-inflammatory and antioxidant properties. The present study will be a double-blind, randomized, placebo-controlled, parallel study in healthy young individuals (18-45 years) consisting of a 3-week endurance training (either moderate intensity continuous training or sprint interval training) period combined with OLE or placebo intake. We will examine the impact of OLE supplementation on maximal exercise capacity, knee extensor neuromuscular function, muscular and blood adaptations. The results of this study will elucidate whether OLE supplementation improves fitness parameters and the molecular mechanisms regulating these adaptations.