LEC4: Programming for Physiological Adaptations - Hypertrophy

Question 1

Hormones in Resistance Training

Answer 1

• Testosterone
• HGH
• Cortisol
• IGF-1

Question 2

What does testosterone do?

Answer 2

Testosterone increases protein synthesis and inhibits protein breakdown rates

RT elicits increase in total testosterone in males, conflicting results show no change to minimal increase in females

Up to 25% ↑ of free T in YOUNG emales post RT (Kraemer & Ratamess, 2005)

Question 2

Where does testosterone production occur in the body?

Answer 2

Male: pituitary gland, adrenal glands, testes
Female: pituitary gland adrenal glands, ovaries

Question 3

Testosterone response to resistance training (RT)

Answer 3

• Free Testosterone ↑ in resistance vs endurance training
• Certain training factors will have a greater influence on testosterone
• Sequencing of exercise
• Intensity OR Volume
• Be careful of a threshold of returns: the Yerkes-Dodson Law (the sweet spot)

Question 4

Testosterone response in females

Answer 4

• Limited concentrations > minimal response to RT
  – No acute increase to heavy RT w/ independent variables of rest and load (Kraemer et.al., 1993)
• Possible chronic adaptation evident with correct programming (Vingren et.al., 2010)
  – Low volume circuit training > ↑ @ 12 weeks / ↓ baseline @ 24 weeks
  – Periodized high volume multi set programming > ↑ @12 weeks / ↑ ↑ @ 24 weeks
• Physiological adaptations to RT may be as a result of growth hormone (GH) in females

Question 4

Human Growth Hormone

Answer 4

• Stimulates the uptake of amino acids into muscles
• Secreted by the pituitary gland during sleep
• RT causes the secretion of GH isoforms with extended half lives allowing for sustained action on target tissue including skeletal muscle
• Can also be associated with the upregulation of IGF-1

Question 5

Human growth hormone (GH)

Answer 5

Temporary elevation of GH ~30min post RT
– Exercise Selection
– Intensity & Volume
– Inter-Set Rest

Question 6

Cortisol

Answer 6

‘”Stress Hormone” > Stress is Stress is Stress

Detrimental to muscle development (Reduced protein synthesis)

Acute response greatest with High Intensity/High Volume…
– Volume may be the biggest driver
– Longer rest periods also seen to ↓ acute response

Possibly buffered by CHO

Question 7

“long-term resistance training program attenuates (reduces the effect) basal, or resting, levels of circulating cortisol”

Answer 7

Less of a significant concern IF the person is habitually resistance trained; MAY be of concern with brand new novel stimulus ie/ mixing in a microcycle of ‘crossfit’ type training or some other exposure to a novel stimulus; greater response with low training age

Question 8

Insulin-Like Growth Factor (IGF-1)

Answer 8

Provides the main anabolic response for the whole body
– Decelerates proteolysis (mm atrophy)
– Promotes hypertrophy by increasing the rate of protein synthesis

RT enhances acute response
– Exact process unclear but understood that IGF-1 released via mechanical stress responsible for ‘kick starting’ hypertrophy response at muscle cellular level (Shoenfeld, 2010)

Chronic levels affected by long-term resistance training
– Resting Levels = Trained > Untrained males
– Small/No change over short term and overreaching protocols

Question 9

Henneman’s Size Principle

Answer 9

States that smaller motor units (motor neurons innervating fewer muscle fibers) are recruited before larger motor units (innervating more muscle fibers) during muscle contractions, allowing for precise and efficient control of muscle force.

Type I: low force production, low recruitment electrical threshold
Type II: higher force production, high recruitment electrical threshold

Question 10

Henneman’s Size Principle: Type I

Answer 10

Type 1 muscle fibers are more oxidative and have a very high training status in most people because they are used constantly.

Question 11

Henneman’s Size Principle: Type II

Answer 11

Type 2 muscle fibers are used infrequently (never in some) and therefore, have a lower training status and are much more responsive to training.

Question 12

Max Rep Exhaustive

Answer 12

Heavier loads, longer rest

Target: muscle hypertrophy
Rep range: 5-12
Intensity (% 1RM): 70-85% (Heavy)
Set Range: 3-4 (to failure)
Tempo (E:P:C): 2-4:1-3:1-3
Interset Rest (min): 2-3

Question 13

Max Set Exhaustive

Answer 13

Moderate loads, big volume

Target: muscle hypertrophy
Rep range: 5-12
Intensity (% 1RM): 50-70% (moderate)
Set Range: 5-10 (to failure)
Tempo (E:P:C): 1-3:1-2:1-3
Interset Rest (min): 1-2

Question 14

Assistant Strength

Answer 14

Classic body building type work, aesthetic

Target: structural balance
Rep range: 8-15
Intensity (% 1RM): 60-80% (moderate)
Set Range: 2-4
Tempo (E:P:C): 1-3:1-3:1-3
Interset Rest (min): 1-2

Question 15

Slow Tempo Exhaustive

Answer 15

High TUT achieved through tempo

Target: muscle hypertrophy
Rep range: 5-8
Intensity (% 1RM): 60-80% (moderate)
Set Range: 3-5
Tempo (E:P:C): 4-6:1-3:4-6
Interset Rest (min): 1-3

Question 16

Low Load Exhaustive

Answer 16

Endurance end of things

Target: muscle hypertrophy/strength endurance
Rep range: 15-30
Intensity (% 1RM): 30-60% (Light)
Set Range: 2-4
Tempo (E:P:C): 1-2:0:1
Interset Rest (min): 2-3

Question 17

Primary mechanisms that effect muscle growth

Answer 17

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

Question 18

Three keys to mechanical tension

Answer 18

1. The nature of tension (active or passive)
2. The role of external resistance
   a. The extent of MU firing frequency is influenced by % external resistance
   b. Larger resistances = Slower contraction velocities = More actin-myosin crossbridging = ↑ in tension that each fiber produces
3. The effects of fatigue
   a. An increase in fatigue decreases contraction velocity
   b. The working muscle fibers become unable to produce the required force to do the work which leads to higher threshold motor units being recruited
   c. Slower speeds = more actin-myosin cross bridging = more mechanical tension on the individual fibers

Question 19

Muscle Damage

Answer 19

Damage can occur to various components of contractile tissue
- Response related to acute inflammatory response
Concentric VS Eccentric?
- Eccentric = ↑ muscle fiber length
- Concentric = ↑ muscle fiber diameter

Question 20

Although muscle growth can occur in the relative absence of muscle damage, potential mechanisms exist whereby muscle damage may enhance muscle hypertrophy

Answer 20

1. release of inflammatory agents
2. activation of satelite cells
3. upregulation of IGF-1 system
4. Set in motion the signaling pathways that lead to hypertrophy

Question 21

_________ exercise has greater hypertrophic effects compared with other types of actions

Answer 21

eccentric

Question 22

Metabolic Stress

Answer 22

Anaerobic glycolysis for ATP results in build up of lactate, hydrogen ions (acid) and phosphates

Muscle ischemia - a restriction of blood flow causing a shortage of oxygen can increase metabolites

Fatiguing sets that produce metabolic stress are directly linked to mechanical tension > more high threshold MU need to be recruited

Question 23

Key point on “A review on the Mechanisms of Blood-Flow Restriction Resistance Training-Induced Muscle hypertrophy”

Answer 23

Mechanical tension and metabolic stress are both primary mechanisms of resistance training induced muscle hypertrophy

Metabolic stress may play the dominant role in mediating the potent hypertrophic effects seen with blood-flow restriction (BFR) resistance training, but mechanical tension also plays a part

Mechanical tension and metabolic stress act synergistically to mediate numerous secondary associated mechanisms, all of which stimulate autocrine and/or paracrine actions for the induction of muscle hypertrophy with BFR resistance training