Hot Topics/ Research/ Healthy Diet / Measuring Energy
Energy Systems
Carbohydrates
Protein
Fat
100

What is the best approach to scrutinize sports nutrition claims?

Develop skills to critically evaluate sports nutrition claims and substantiate or refute them with evidence.

100

Explain the fate(s) of lactate

if lactate concentrations get too high, lactate is converted to pyruvate (Cori Cycle/ Gluconeogenesis) and taken into the mitochondria of highly aerobic cells. Once inside the mitochondria, this compound is metabolized aerobically

100

What CHO recommendations post-exercise? 

first hour? 

up to 4 hours? 

–1-1.5 g/kg body weight in first hour

–1-1.2 g/kg each hour for up to 4 hours

100

What are BCAAS? Does supplementation work? 

Leucine, isoleucine, valine

studies show promise for immune system support, cognition and reduction of postexercise fatigue lower serotonin by competing with its precursor tryptophan for crossing the BBB)

100

How do SCFA and LCFA vary in their absorption? 

Does MCT oil increase fat burning? 

1.SCFA and MCFA uptake by enterocytes do not require FA transporters, but LCFA require fatty acid transport proteins (FAT/ CD36, FABP)

MCT oil showed very little to no ergogenic effects on exercise performance and substrate utilization in healthy populations

200

Sports Nutrition can be defined as?

What are the short and long term goals?

The integration and application of scientifically based principles to support and enhance training, performance, and recovery


Short term goals - 

•Consumption of food and beverages to delay fatigue during training and competition

•Minimization of dehydration and hypohydration

•Utilization of dietary strategies beneficial for performance, such as precompetition meal, appropriately timed caffeine intake, or carbohydrate loading

•Intake of nutrients that support recovery

•Appropriate timing of nutrients

Long term goals - Adequate overall diet to maintain good health and support a healthy immune system; Adequate replenishment of muscle and liver glycogen with dietary carbohydrates; Adequate protein intake for growth and repair of tissue, particularly skeletal muscle

200

How does creatine supplementation assist with the phosphagen system? Explain the creatine shuttle. 

•Increases creatine and phosphocreatine concentrations

The creatine shuttle Rephosphorylation of creatine phosphate from creatine via aerobic metabolism. Creatine that remains from chemically splitting creatine phosphate is phosphorylated using energy from ATP produced aerobically in the mitochondria of the muscle. This process requires an increase in aerobic metabolism (oxidative phosphorylation) and returns creatine phosphate concentrations to normal within a minute or two.

200

Explain glucose homeostasis and hormones that are involved.

Insulin

Uptake and storage of glucose and FFA

Plasma concentration decreases during exercise

Decreased insulin response following training

Glucagon

Mobilization of glucose and FFA fuels

Plasma concentration increases during exercise

Decreased response following training

200

Explain two AA supplements that may improve performance and their proposed benefits

Beta-alanine - increase carnosine, buffering capacity 

HMB - metabolite of leucine, effectiveness with muscle recovery with HIT exercise

Arginine - stimulate GH release if taken before exercise 

BCAAs - cognition and reduction of postexercise fatigue

200

Explain the metabolism of fats

2. Within an adipocyte, hormone-sensitive lipase will break down a stored triglyceride into glycerol and three fatty acids, which diffuse into the capillary circulation.

3. Then are metabolized through β-oxidation to generate Acetyl CoA to enter into the Krebs cycle and undergo OXPHOS

4. The fatty acids are bound to albumin for transport.

5. This process is initiated with the stimulation of adrenergic receptors on the cell membrane by stress hormones such as epinephrine and norepinephrine.

300

What are the components of EE and how does it relate to athletic performance?

•Resting metabolic rate

–Amount of energy required to maintain nonactive but alert state

–~50-70% daily expenditure

•RMR prediction equations

–Mifflin St. Jeor

–Harris-Benedict

–Cunningham equation (requires LBM)

•Thermic effect of food

–Digestion and absorption of food

–~10-20% of daily expenditure

•Physical Activity

–Activities of daily living

–Exercise

–~20%

•Energy available to perform all other functions after energy cost of exercise is subtracted

300

What is the purpose of the ETC? 

–Electrons passed along series of complexes

–O2 is final acceptor, picking up electrons in form of Hydrogen to form water

Electrons power ATP production

300

Explain what it means to "Hit the Wall" and what you can do to prevent this. 

2. Why are fats important for CHOs?

Hitting the wall - inability to maintain exercise intensity** 

Caused by glycogen depletion because ”fats burn the flames of carbohydrates”

Carbohydrates prime the Krebs cycle with Krebs cycle intermediates (glycolysis). This speeds up the Krebs cycle and improves fat metabolism


Prevention: Glycogen loading / supercompensation

300

Explain the effects of pre-sleep casein

Pre-sleep casein protein intake (30–40 g) increases overnight MPS and metabolic rate without influencing lipolysis.

Casein-based protein consumed in the morning (10 am) and evening (10:30 pm) was more beneficial for increasing fat-free mass than consuming the protein supplement in the morning (10 am) and afternoon (~3:50 pm)

300

Explain the fat burning myth

Fat Burning Zone Myth - where a maximal proportion of fat is burned – states we burn more fat calories at low intensity than at high intensity

As exercise intensity increases, there is a decrease in the % of Fat used as a fuel source and an increase in the % of CHO used as a fuel source, but the TOTAL calories EXPENDED GOES UP – WE ACTUALLY HAVE A GREATER NUMBER OF FAT CALORIES EXPENDED DURING HIGH INTENSITY

400

Explain the sliding filament theory

Use of ATP by muscle

  1. Acetylcholine (released by motor neuron) combines with receptors on muscle fiber, causing depolarization and an action potential. 

  2. Impulse spreads through T tubules, stimulating Ca2+ release from sarcoplasmic reticulum.

  3. Ca2+ binds to troponin, causing change in shape. Troponin pushes tropomyosin away, exposing binding sites on actin filaments.

  4. ATP is split. Myosin head, now cocked, binds to exposed binding site, forming crossbridge.

  5.  Pi is released.

  6. Crossbridge ­flexes, and actin filament is pulled toward center of sarcomere. This movement is the power stroke. ADP is released.

  7. Actin-myosin complex binds ATP, and myosin detaches from actin.

400
Explain the absorptive and postabsorptive fuel utilization state in the muscle 

*Hint, table in Ch 3

Absorptive state - 

Glucose used for energy or stored as glycogen

Post absorptive state - Glucose used for energy, some glycogen storage continues; lactate and alanine released to liver to make glucose; fatty acid uptake (provided by the breakdown of fat from adipose tissue) for use as energy

400

Explain CHO timing for 

>60 min 

45-60 min

>60 min-2.5 hr

>2.5-3 hr

1-4 g/kg

45- 60 small amounts 

>60 min-2.5 hour - 30-70 g (depends on tolerability)

>2.5-3 hr  up to 90 g

400

Explain the types of protein supplementation benefits to increase muscle adaptations from resistance training 

How much? How often? 

High content in essential AAs. 

~20-40 g/ every couple of hours

Whey protein ingested close to resistance exercise, promotes a higher activation (phosphorylation) of mTOR (a key signaling protein found in myocytes that is linked to the synthesis of muscle proteins) – soy is another fast-absorbing protein

- Whey shows an advantage over soy (higher EAA/ Leucine content) – greater activation of MPS

400
What are some long term adaptations of the ketogenic diet? 

•Decreased muscle and liver glycogen storage and rate of breakdown

•Increased gluconeogenesis

•Increased muscle triacylglycerol storage and utilization

•Increased mitochondrial oxidative capacity

•Increased ketone production

•Decreased use of glycolysis-derived acetyl CoA

500

Explain the Paleo diet, vegan, omnivore, and gluten-free diet with consequences and benefits

Paleo - meat, fish, shellfish, fruits, veggies, poultry, eggs, roots

•Positively impacts health outcomes, rich in nutrients/ vitamins

•body composition

•glucose tolerance

CON: Can't sustain performance during high volume periods


Vegan - 

Pro: inclusion of antioxidants (polyphenols), micronutrients (vitamin C, E), and carbohydrate-rich foods, lower in total and saturated fat and higher in n-6 fats

Con: lower energy intake, may be deficient in some nutrients (e.g., calcium, vitamin D, B12, iron, zinc, iodine), lower n-3 fatty acid levels, could reduce creatine and muscle carnosine stores


Omnivore - 

Pro: meets requirements for calcium, vitamin D, B12, iron, zinc, iodine, provides complete protein recommendations

Con: often lacks polyphenols, 58% and 81% more meat and calories than the recommended intake for women and men, excessive iodine, high saturated fat; arachidonic acid, a fatty acid found in meat and linked to lower mood - Depressive symptoms


Gluten - 

Pro: weight loss, disease cure/mitigation, readily convert to glucose

Con: low fiber, high fat, low B vitamins, iron, calcium, & zinc, cost, short term, addiction

500
What are the predominant energy systems for the following activities: 

100 yd dive

200m sprint

800 m sprint

Volleyball 

Tennis

100 yd dive - ATP/PCR

200 m sprint - ATP/PCR

800 m - Glycolytic 

Volleyball - ATP/PCr

Tennis - glycolytic/ aerobic 

500
Explain the two types of CHO loading 

and how you can increase speedy refueling

Bergstrom - deplete glycogen stores with hard exhaustion coming up to a race then try to decrease exercise with a high CHO diet

Sherman – HIGH CHO then taper exercise volume down – 

Speedy refueling can be accomplished by 1-1.2 g/kg for first 4 hr then resume daily needs

500

Meat vs plant-based proteins. Is one better than the other? Explain. 

1. vegetarian diets often lack equivalent amounts of protein. However, with proper supplementation and careful nutritional choices, it is possible to have complete proteins in a vegetarian diet

2. high-quality, animal-based products (meat, milk, eggs, and cheese) an individual will achieve optimal growth as compared to ingesting only plant proteins. Increased lean mass and decreased fat mass more than the control and soy groups.

3. Soy - may also be responsible for inhibiting growth factors and protein synthesis via its negative regulation of mTOR

500

Explain the ketogenic diet and its effect on HIIT and endurance training. 

>4 weeks adaptations 

greatest oxidative adaptations - Long-term adaptation to LCHF diets produces even greater metabolic benefits, including a higher rate of fat oxidation and lower rates of carbohydrate oxidation and glycogenolysis

HIIT? 

•Only a few studies have examined the impact of LCHF diets on high-intensity exercise. Several of them failed to account for the changes in body weight and/or body composition and training status

  No clear evidence in short term adaptations (~4-5 days) to a high fat diet in athletes to increase performance

•Long-term LCHF diet may enhance performance in ultra-endurance events such as the ultra-marathon and ironman triathlon by supporting a higher fat oxidation rate at higher relative exercise intensity and by having a glycogen sparing effect

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