Unit 3 - Lecture 20

Question 1

Three Stimulus for Hypertrophy Adaptation

Answer 1

1. Nutrition
2. Stress
3. Hormones

Question 2

Nutrition for Hypertrophy

Answer 2

1. Energy Balance
2. Protein Consumption
   
   1. Sedentary = 0.8 g/kg
   2. Athletes = 1.2-1.5 g/kg
      
      1. Endurance = 1.2 g/kg
      2. Resistance = 1.5 g/kg
   3. Older Individuals = > 1.6 g/kg

Question 3

Stress for Hypertrophy

Answer 3

1. Load
   
   1. Mechanical Tension
   2. Muscle Damage
   3. Metabolic Stress

Question 4

Hormones for Hypertrophy

Answer 4

1. IGF-1
2. Testosterone

Note:
*Insulin is better for preventing muscle protein breakdown

Question 5

Changes in Baseline mRNA, Protein, Performance vs. Time

Answer 5

In the short term, there are oscillatory changes in mRNA, while protein and performance are unchanged. As time continues, there are increases in each category.

Question 6

Muscle Fibers:

Type I = _____

Type IIa = _____

Type IIx = _____

Answer 6

Slow

Intermediate/Adaptable

Fast

Question 7

Physiologic Process for Hypertrophy:

Answer 7

• IGF-1 targets the cellular protein AKT.
• AKT stimulates mTOR.
  
  • Key protein sensor for protein synthesis in tissue.
• mTOR stimulates protein synthesis.

Question 8

Physiologic Process for Atrophy:

Answer 8

1. Cortisol inhibits AKT (which will also inhibit mTOR).
2. With limitations in AKT, the transcriptional factor FOXO upregulates.
3. FOXO enhances protein degradation.
   
   1. Increase ubiquitin ligases.

Note:

1. Cortisol increases proteolysis.
2. During long-duration exercise, cortisol will increase in order to stimulate protein oxidation to create glucose via gluconeogenesis in the liver.
   
   1. Same idea for an overnight fast.
3. However, with too much stress in our lives, we will inhibit pathways that promote protein synthesis and stimulate pathways that up-regulate proteins like FOXO to promote protein oxidation.

Question 9

Recruitment of muscle fibers is key for optimal adaptation.

Answer 9

To recruit the muscle fiber you want to adapt, you need to train in the proper intensity range. Higher intensities stimulate Type IIx fibers, and lower intensities stimulate Type I muscle fibers.

*Muscle fibers have different profiles (cumulative final type question).

Question 10

The ability to produce maximal force is _______.

Answer 10

Strength

Question 11

How do we gain strength?

Answer 11

Increase demand of the system and create an overload. (Progressive Overload)

Question 12

What are the loads/reps that can achieve strength?

• Strength
  
  • __ - __ reps
  • Load (% 1RM) - ~ ___ %
• Power
  
  • __ - __ reps
  • Load (% 1RM) - ~ ___ %
• Endurance
  
  • __ - __ reps
  • Load (% 1RM) - ~ ___ %

Answer 12

• Strength
  
  • 1- 4 reps
  • Load (% 1RM) - ~ 100%
• Power
  
  • 1-6 reps
  • Load (% 1RM) - ~ 70%
• Endurance
  
  • 12-16+ reps (*AMRAP - Failure)
  • Load (% 1RM) - ~ 50%

Strength and Power will target Type IIx. Endurance will target Type I fibers.

Question 13

Testosterone and Growth Hormone

Answer 13

• Both activate mTOR
• Stimulated by Acidosis (Increased H+)
  
  • Longer duration working sets will stimulate anaerobic glycolysis.

Question 14

Steroid hormones are synthesized by _________.

Answer 14

Cholesterol

• Clinical blood cholesterol < 200 mg/dL.
• Dietary intake < 300 mg/day.
  
  • This is highly debated. There is a debate that eating higher cholesterol levels are good for hypertrophy because it will synthesize more steroid hormones. Evidence suggests potentially closer to 800mg/day for hypertrophy.

Question 15

The greater the intensity of exercise, the ______ the stimulus we see in hormones.

Answer 15

Greater

• Lower limbs in particular most likely due to muscle activation (largest muscle groups in the body).

Question 16

_______ is a contributor to male characteristics.

_____ characteristics are anabolic.

_____ characteristics are androgenic.

Answer 16

Testosterone

Muscular

Masculine

Question 17

Two conversions of testosterone.

Answer 17

1. Estradiol
   
   1. Female sex characteristics.
2. DHT (5-reductase enzyme)
   
   1. Secondary sex characteristics
   2. Contains three times the androgenic properties, but only 50% anabolic.

It is worth mentioning that there are sex characteristics to these hormones.

Question 18

Anabolic Steroids are designed to mimic _______ via ______ actions.

Answer 18

Testosterone; Anabolic

Question 19

Two types of anabolic steroids.

Answer 19

1. Oral
2. Injectable

Question 20

Oral Steroid Characteristics

Answer 20

1. Broken down fast.
2. High frequency of dosing.

Question 21

Injectable Steroid Characteristics

Answer 21

1. Longer half-lives (than oral steroids) - up to 30 days.
2. Large doses.
3. Contain a methylated group
   
   1. Help prevent breakdown in the liver.

*Injectable steroids are associated with liver dysfunction.

Question 22

Testosterone is easy to detect in the blood. What do athletes take as a workaround?

Answer 22

Pro-Hormone supplements

The idea is that pro-hormone raw materials are going to provide precursor molecules to the body in order for the body to develop testosterone.

Question 24

What are two popular prohormones?

Answer 24

1. DHEA (dehydroepiandrosterone)
2. Androstenedione
   
   1. In theory, will increase testosterone.

The evidence is not there that these work (in untrained populations). However, there is evidence that these can increase FFM and strength in trained people.

Question 25

Should steroid and prohormone users be concerned about side effects?

Answer 25

• Yes, due to the negative biofeedback mechanisms.
  
  • Hypothalamus > Gonadotropin-Releasing/Inhibiting Hormone (GnRH/GnIH) > Anterior Pituitary > FSH + LH > Testes > Testosterone

Exogenous androgen supplementation will stimulate testosterone and inhibit the anterior pituitary gland and the hypothalamus.

Taking steroids can reduce your body’s ability to produce endogenous testosterone.

Steroid effects > Pro-hormone - much greater.

Question 26

Vitamin D precursor is located in the ____.

Answer 26

Skin

Question 27

What is the mechanism of action for the production of Vitamin D3?

Answer 27

Skin > Vitamin D₃ > Liver > 25-Hydroxy-Vitamin D₃ (25(OH)D₃ > Kidney > 1,25 Dihydroxyvitamin D₃ (Active Form)

• Need 10-15 minutes of sun exposure to activate this process.
• Due to latitude in the United States, from November to February Vitamin D is very hard to make.
  
  • Clothing

Question 28

Low serum levels of Vitamin D (< 25 nM)

Answer 28

• Weakness
• Functional declines
• Higher fracture rates/falls.

Question 29

How does Vitamin D relate to hypertrophy?

Answer 29

• Myogenesis
  
  • Increase Satellite Cell Activation
  • Increase Myoblast Proliferation
• Muscle Protein Synthesis Increase
  
  • C₂C₁₂ Muscle Cells (Rodent derived muscle cells)
    
    • Increase AKT; Increase mTOR
    • Decrease Myostatin
      
      • Inhibits mTOR (inhibits protein synthesis).

Evidence is accumulating in humans, but it is very limited.

Question 30

“Anabolic Resistance”

Answer 30

*% FSR = Fractional Synthesis Rate

In younger people, resistance training will cause a rise in the fractional synthesis rate of muscle, practically muscle protein synthesis.

In older adults, the response is blunted.

As you age, you may not derive the same response to exercise as a younger adult.

Is it aging? Obesity? Insulin Resistance? Physical Activity?

Some suggest that higher doses of exercise will work (Intensity? Volume?)

Question 31

The first adaptation to resistance exercise is neural, followed by strength and then hypertrophy.

Answer 31