The first step in muscle growth is an increase in protein synthesis, and a decrease in protein breakdown. Our hormones are directly involved with both protein synthesis, and breakdown. The hormonal system supports normal function of the body, and helps it respond to external stimuli such as heavy resistance training. Hormones are chemical messengers that are made, stored, and then released into the blood by different endocrine glands, such as pituitary, thyroid, and adrenal glands to name a few.
Hormones are secreted both during, and after resistance training. Muscle remodeling takes place due to these hormonal secretions, and our aim is for these hormonal changes to be of the anabolic variety. In the situation where we had a heavy training session, catabolic actions in the muscles may occur as a result of the inability of anabolic hormones to bind to the receptors.
Examination of the main hormones involved in resistance training and the ways in which to increase their anabolic output, while also limiting the role of catabolic hormones, will help when determining the appropriate training program.
Testosterone is the primary hormone that interacts with skeletal muscle tissue. Testosterone’s role is vital in muscular development. Most research has been undertaken on male subjects, and although there are variations between the different genders, similar training protocols can be followed, even though women have at most 1/10 the testosterone concentration that men do.
To increase testosterone levels, consider that testosterone levels are typically highest in the morning, and drop with time during the day. This makes gains in the morning easier, but if we train in the afternoon our total testosterone levels will be higher throughout the entire day, since resistance training increases testosterone output. Training using predominantly large-muscle group exercises such as squats, deadlifts, pull-ups/chins will have the largest impact on testosterone levels. Perform high intensity, heavy resistance, or combine high volume, multiple sets of an exercise with short rest periods to maximize testosterone output.
Growth Hormone, also known as somatotropin, is naturally secreted by the pituitary gland. GH is vital in the normal development of children, but it is also a major link in adapting muscles to resistance training. There are many synthetic GH supplements on the market today, however exercise-induced GH secretion is very different from GH injections. The hypertrophy seen from exercise induced GH shows a much higher force production than does synthetic GH.
The major physiological uses of Growth Hormone are the decreased use of glucose, and an increased use of fat breakdown for energy. Also, increased protein synthesis, and enhanced immune function.
The largest increases in GH levels are seen while undertaking the following training guidelines – 10 repetitions at heavy resistance - 3 sets of each exercise - 1 min rest intervals. Consume both carbohydrates, and protein before and after workouts. Perform interval type of cardiovascular exercise at high intensity, such as rowing, skipping, or running sprints.
Many of the GH effects are transported through insulin like growth factors. IGF-1 is the primary IGF involved with respect to exercise. IGF has a major role in protein synthesis. Responses of IGF-1 to heavy resistance training however, remain unclear, and are currently being investigated by researchers worldwide.
Epinephrine is a catecholamine that is secreted by the adrenal medulla and is important in strength and power activities. It is usually one of the first endocrine functions to occur in response to resistance exercise. This hormone acts as the central motor stimulator, peripheral vascular dilator, and enhances the enzyme system in muscle.
Some of the physiological functions of epinephrine include increased muscle contraction rate, increased blood pressure, increased energy availability, and increased blood flow. Epinephrine augments the secretion rates of other hormones, such as testosterone. Heavy resistance training has been shown to increase epinephrine levels during maximal exercise.
Ultimately we want all of these hormones working in our favor when we are undertaking a muscle building program.