1. Endocrine system
Module 4- Training

2. Endocrine System
Like the nervous system, the endocrine system helps to control and coordinate the functions of the body’s systems
But the endocrine system doesn’t use electrical signals that travels down the nerves,
The endocrine system uses hormones that travel through the blood stream
Hormones are detected by receptors on cells
Each hormone has a specific receptor

3. Two types of Hormones Peptide (Polypeptide) Hormones
Bind to receptors that are located on the cell membrane
This causes a cascade of events in the cell that result in a change of some kind in the cell’s function or in the steps leading to protein synthesis

4. Peptide (Polypeptide) Hormones

5. Two types of Hormones Steroids
Enter the cell, combine with a receptor in the cytoplasm, and bind to a specific site on the DNA located in the cell nucleus
This binding stimulates the RNA transcription/translation processes, resulting in the synthesis of proteins

6. Steroid Hormones

7. Hormones
Many hormones are produced and released by glands

8. Hormones Not simple one-task molecules
Cause different cell functions based on the type of cell being bound
Interact with other hormones or molecules to alter their own function
Hormone concentrations are not constant
Naturally vary within a day (diurnal variation)
Vary day to day (eg. Menstrual cycles)
Respond to stress (exercise)

9. Catecholamines Epinephrine, norepinephrine, dopamine Function
Polypeptide hormones
Function
Vasoconstriction of non-working tissue blood supply allowing blood redistribution (leads to increased blood pressure)
Causes an increase in energy availability via metabolic enzyme activity and increase in contraction rate
Influence on central nervous system leads to increased force production
Acute Response
Nervous system causes an increase
Chronic Adaptation
Chronic exposure to high levels causes body to decrease catecholamine level at submaximal level, at maximum exercise level higher levels are still released

10. Cortisol Function Acute Response Chronic Adaptations
Stimulation of gluconeogenesis (convert amino acids to glucose)
Increased activity of enzymes that degrade proteins (proteolysis)
Inhibition of protein synthesis
Acute Response
Increased as a result of resistance training, particularly when volume is high and rest periods are short
Chronic Adaptations
No consistent findings, chronic higher levels are associated with impaired immune function and overtraining
Manipulating Cortisol (and other adrenal hormone) release
Perform a high volume of repetitions
Exercise large muscle groups
Take short rest periods
Vary this training protocol periodically to avoid overuse or overtraining

11. Growth Hormone (Somatotropin)
Functions
Increased lipolysis, fat metabolism, collagen synthesis and cartilage growth, renal function and retention of electrolytes
Enhanced immune cell function and spares glucose
Acute Response
Increases with both resistance training (especially longer duration/higher repetitions and shorter rest periods) and aerobic exercises
Women have higher GH levels than men and a higher response than men (may be due to interactions of other hormones)
Chronic Response
No consistent findings, more research needed
Stimulating GH Through Resistance Training
High intensity exercises that result in elevated lactate levels (10 RM)
Multiple sets (at least three)
Short rest period (one minute or less)

12. Testosterone Function Acute Response Chronic Adaptation
Stimulates protein production and expression of male sex characteristics
Acute Response
Increases with heavy resistance exercise in men, unsure of response in females
Chronic Adaptation
Increase after two years of intense training in males, unsure with females
Manipulating Testosterone Response
Exercises that use large muscle mass
Heavy loads (85-95% 1RM)
Moderate to high volume (multiple sets and exercises)
Short rest intervals (30 to 60 seconds)