Updated ExPhys Exam 3

John O. Holloszy

Considered father of modern exercise biochemistry

Studied aerobic exercise, nutrition and muscle development changed the way elite athletes train and helped others better cope with hear disease, diabetes, obesity and aging

Endurance Primary Signaling

AMP/ATP

Endurance Secondary Signals

AMPK

Endurance Relay Mesenger

PGC1a

Endurance Outcomes

Mitochondrial biogenesis

Dr. Bengt Saltin

His famous “bed rest” study transformed medical practice on how people recover from heart attacks, general surgery, or injury.

Detraining

50% of mitochondrial content lost after 1 week of detraining

takes 4 weeks to recover from 1 week of detraining

Outcomes of Resistance Training

Neural activation

Muscle growth

• Hypertrophy

• Hyperplasia

Resistance Outcome: Nervous System

When one arm is trained, the other am improves in strength solely due to neural adaptation

Primary Signal for Resistance Training

Mechanoreceptor Activation

Resistance Primary Receptors

Phosphatidic acid (PA)

Rheb release

Secondary Messenger Resistance

mTOR activation

Resistance Outcome

Protein Synthesis

Hypertrophy

• Increase in size of muscle fiber dur to an increase of myofibrillar proteins

• Increase in muscle fiber cross-sectional area

Training Principles - Overload

Training effect occurs when a system is exercised at a level beyond which it is normally accustomed

Training Principles - Specificity

Specific to: muscle fibers involved, energy system involved, velocity of contraction, type of contraction

Training Principles - Reversibility

Gains are lost when overload is removed

Training Principles - Progression

Manipulating program variables to continually increase training stimulus over time

Training Principles - Regularity

Training must occur on a regular basis because adaptations cannot be stored

Intensity for Strength Gains

8-12 Reps

Number of sets for strength gains

2+ sets

over 10 sets are not reccomended

Frequency for strength gains

2-4 days per week

4-6 days if using a “split” routine

Nutrition Fundamental Priority 1

Energy: Adequate kcal intake

Nutrition Fundamentals Priority 2

Macronutrients: balancing Carbs, Fats, Proteins

Nutrition Fundamentals Priority 3

Micronutrients: Optimizing micronutrient intake

Nutrition Fundamentals Priority 4

Supplements: supplementing any gaps in diet

Nutrition Fundamentals Priority 5

Putting it all together: adjusting as necessary

Symptoms of DOMS (Delayed Onset Muscle Soreness)

• Decreased Performance

• Loss of Body Weight

• Increased Number of Infections

• Chronic Fatigue

• Elevated HR and Blood Lactate Levels during Exercise

• Psychological Staleness

DOMS

Appears 24-48 hours AFTER strenuous exercise

Due to microscopic tears in muscle fibers or connective tissue

Steps Leading to DOMS

1) Structural Damage to muscle fiber

2) Membrane Damage

3) Calcium ions leak out of the sarcoplasmic reticulum

4) Protease Activation - results in breakdown of cellular proteins

5) Inflammatory Response

6) Edema and Pain

Potential mechanisms of DOMS

Muscle Fiber Damage

• Z-line streaming

• Sarcolemmal Damage

Allows for:

• Intracellular compartments to leak out of the fiber

Results in

• Increased serum creatine kinase after intense exercise

• increases protease activity

• Inflammation

Repeated Bout Effect

A bout of unfamiliar exercise results in DOMS

Following recovery, another bout of the same exercise results in minimal injury

Theories for repeated bout effect

Neural Theory

Connective Tissue Theory

Cellular Theory

Neural Theory

Recruitment of larger number of muscle fibers

Connective Tissue Theory

Increased connective tissue to protect muscle

Cellular Theory

Synthesis of protective proteins within muscle fiber

Describe the effects of detraining on VO2max, HRmax, SVmax, Q (CO)max (a-vO2 diff) max. Explain the effects of training, detraining and retraining on mitochondrial content

Detraining causes a RAPID decrease in VO2max

• about 8% in 12 days, 20% after 84 days

Decreasing SV

• Rapid loss of plasma volume

Decrease A-VO2max

• Decrease Mitochondria

• Decrease oxidative capacity of muscle

  • Decrease IIa fibers, increase IIx fibers

Training to Increase VO2Max

Large Muscle groups, Dynamic Activity

20-60 min, 3-5 times/week, 50-85% VO2Max

Expected Increase in VO2Max

Average = 15%

2-3% in those with high initial VO2Max

Up to 50% in those with low initial VO2max

Genetic Predisposition

Accounts for about 50% of VO2max

Prerequisite for very high VO2max

Increasing Stroke Volume

Increase Preload (EDV)

Decrease Afterload (TPR = Total Peripheral Reistance)

Increasing Preload (EDV)

• Increase Plasma Volume

• Increase Venous Return

• Increase Ventricular Volume

Decrease Afterload

• Decrease Arterial Constriction

• Increase maximal muscle blood flow with no change in mean arterial pressure

• Increase contractility

Arteriovenous O2 Difference

• Increase Muscle blood flow

  • Decrease SNS vasoconstriction

• Improved ability of the muscle to extract oxygen from the blood

  • Increase capillary density

  • Increase mitochondrial number

What are reasonable VO2 max values in ml/kg/min for an elite cross country skier vs. a sedentary individual.

84M/72F for cross country skier, 45/35M / 38/30F for young sedentary/middle age sedentary respectfully

Describe a general exercise Rx to increase strength, and the time course of adaptation to strength training.

-          8-10 multi-joint exercises

-          2-4 sets

-          8-12 reps

-          Executed with proper technique

-          Using full ROM

-          Regular breathing pattern

-          Train each muscle group 2-3 days per week

-          To increase strength, progressive overload should be followed, and reassessment should be conducted periodically

Describe the potentially inhibitory effects of endurance exercise on resistance training. What Is the potential inhibitory pathways

Endurance training can increase the release of AMPK, then increasing TSC ½ which then inhibits mTOR from increasing which leads to protein synthesis and muscle hypertrophy inhibiting resistance training gains