Skeletal muscle is a muscle that is connected to one or both ends of the skeleton to be part of the mechanical system that moves the limbs and other parts of the body. The human body contains more than six hundred skeletal muscles, which make up forty to fifty percent of the total body weight. Nonetheless, skeletal muscles perform three important functions: force generation for locomotion and respiration, force generation for postural support, and heat production during cold stress. The most obvious function of skeletal muscles is to allow an individual to move freely and breathe. Skeletal muscles are attached to bones by tough connective tissue called tendons. The muscles that decrease joint angles are called muscles. The muscle adapts to multiple aerobic exercises to become a more efficient energy supplier. It is important to know that regular endurance exercise has great benefits on a person's overall health, including the prevention of diabetes, obesity and cardiovascular disease. However, muscles adapt to anaerobic and aerobic training. Chronic exercise stimulates change in body systems. Systems will also adjust for volume, levels and intensity. Several factors affect adaptations to training. Factors include genetic background, environmental factors, age, gender and exercise training status. With anaerobic metabolism, high-intensity, short-duration exercise primarily comes from stored phosphagens and adenosine triphosphate. Aerobic metabolism contains most of the energy, more than fifty percent, required for prolonged exercise lasting more than three minutes (Morton, RW2015). Anaerobic training can cause neuronal adaptation in some cases. Several neuronal changes related to anaerobic training occur along the lower corticospinal pathways. Skeletal muscle adapts to anaerobic training primarily through hypertrophy, hyperplasia, and by improving its biochemical and ultra-structural components. Hypertrophy involves an increase in the synthesis of the contractile proteins actin and myosin. However, motor units that contain type I or type II fibers are nonetheless more effective in removing plasma triglycerides, free fatty acids, and glucose. Endurance exercise increases the mitochondria and glucose begins to be transported into the muscles. Additionally, endurance exercises like prolonged running lead to an increase in muscle respiratory capacity. However, this adaptation includes an increase in components of the mitochondrial respiratory chain (Agergaard, J. 2015). Muscular adaptation to aerobic exercise is similar to adaptation to strength training. When performing aerobic exercises, the number of mitochondria begins to increase. Not to mention that cardiovascular training increases the number of capillaries that bring oxygen to the mitochondria. With more fuel in the muscles, they can endure longer periods of exercise, but adaptations have their various limits. Despite the duration and intensity of a person's training, it is essential to understand that a person can reach peak efficiency in as little as four or five weeks. Fitness training is also an adaptive process and the body will begin to adapt to the stress of exercise with increased fitness above a moderate intensity threshold. To achieve greater efficiency, always consider the factors